answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
Práce: 80 J. | null | phy_0301 | worked_example | cs | Síla 20 N tlačí na dráze 4 m. Spočítej vykonanou práci. | [
"W = F×d.",
"W = 20 N × 4 m.",
"= 80 J."
] | physics | Answer: Práce: 80 J.
Steps:
1. W = F×d.
2. W = 20 N × 4 m.
3. = 80 J. | mechanics |
The answer is Transformer. | {
"A": "Motor",
"B": "Transformer",
"C": "Battery",
"D": "Fuse"
} | phy_0302 | multiple_choice | en | Choose: what scales by turns? | [
"Voltage ratioed.",
"So: Transformer.",
"Select option B."
] | physics | Answer: Transformer
Steps:
1. Voltage ratioed.
2. So: Transformer.
3. Select option B.
Answer: (B) | electromagnetism |
Teplota měří průměrnou kinetickou energii částic. | null | phy_0303 | concept | cs | Co je teplota? | [
"Teplota měří průměrnou kinetickou energii částic.",
"Odpověď tedy platí: Teplota měří průměrnou kinetickou energii částic."
] | physics | Answer: Teplota měří průměrnou kinetickou energii částic.
Steps:
1. Teplota měří průměrnou kinetickou energii částic.
2. Odpověď tedy platí: Teplota měří průměrnou kinetickou energii částic. | thermodynamics |
The answer is Snell's law. | {
"A": "Ohm's law",
"B": "Snell's law",
"C": "Hooke's law",
"D": "Boyle's law"
} | phy_0304 | multiple_choice | en | Choose: what predicts bends? | [
"Sines scaled.",
"So: Snell's law.",
"Select option B."
] | physics | Answer: Snell's law
Steps:
1. Sines scaled.
2. So: Snell's law.
3. Select option B.
Answer: (B) | optics |
Shakes run along travel in compressions, like sound in air. | null | phy_0305 | concept | en | Why longitudinal? | [
"Shakes run along travel in compressions, like sound in air.",
"So the answer stands: Shakes run along travel in compressions, like sound in air."
] | physics | Answer: Shakes run along travel in compressions, like sound in air.
Steps:
1. Shakes run along travel in compressions, like sound in air.
2. So the answer stands: Shakes run along travel in compressions, like sound in air. | waves |
Quantum states blend possibilities until measurement picks one. | null | phy_0306 | concept | en | What is superposition? | [
"Quantum states blend possibilities until measurement picks one.",
"So the answer stands: Quantum states blend possibilities until measurement picks one."
] | physics | Answer: Quantum states blend possibilities until measurement picks one.
Steps:
1. Quantum states blend possibilities until measurement picks one.
2. So the answer stands: Quantum states blend possibilities until measurement picks one. | modern |
Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola. | null | phy_0307 | concept | en | What is projectile motion? | [
"Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola.",
"So the answer stands: Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola."
] | physics | Answer: Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola.
Steps:
1. Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola.
2. So the answer stands: Horizontal velocity stays constant while gravity accelerates downward, tracing a parabola. | mechanics |
Charges in fields feel qvB pushes sideways, bending beams and currents. | null | phy_0308 | concept | en | Why Lorentz force? | [
"Charges in fields feel qvB pushes sideways, bending beams and currents.",
"So the answer stands: Charges in fields feel qvB pushes sideways, bending beams and currents."
] | physics | Answer: Charges in fields feel qvB pushes sideways, bending beams and currents.
Steps:
1. Charges in fields feel qvB pushes sideways, bending beams and currents.
2. So the answer stands: Charges in fields feel qvB pushes sideways, bending beams and currents. | electromagnetism |
Kelvin začíná v absolutní nule. | null | phy_0309 | concept | cs | Proč Kelvinova stupnice? | [
"Kelvin začíná v absolutní nule.",
"Odpověď tedy platí: Kelvin začíná v absolutní nule."
] | physics | Answer: Kelvin začíná v absolutní nule.
Steps:
1. Kelvin začíná v absolutní nule.
2. Odpověď tedy platí: Kelvin začíná v absolutní nule. | thermodynamics |
The answer is Polarizer. | {
"A": "Amplifier",
"B": "Heater",
"C": "Polarizer",
"D": "Timer"
} | phy_0310 | multiple_choice | en | Choose: what cuts glare? | [
"Direction filtered.",
"So: Polarizer.",
"Select option C."
] | physics | Answer: Polarizer
Steps:
1. Direction filtered.
2. So: Polarizer.
3. Select option C.
Answer: (C) | optics |
Počet cyklů za sekundu v hertzích. | null | phy_0311 | concept | cs | Co je frekvence? | [
"Počet cyklů za sekundu v hertzích.",
"Odpověď tedy platí: Počet cyklů za sekundu v hertzích."
] | physics | Answer: Počet cyklů za sekundu v hertzích.
Steps:
1. Počet cyklů za sekundu v hertzích.
2. Odpověď tedy platí: Počet cyklů za sekundu v hertzích. | waves |
Mass number is 8. | {
"A": "8",
"B": "7",
"C": "9",
"D": "10"
} | phy_0312 | multiple_choice | en | A nucleus has 4 protons and 4 neutrons. What is its mass number? | [
"A = 4 + 4.",
"A = 8.",
"Select option A."
] | physics | Answer: 8
Steps:
1. A = 4 + 4.
2. A = 8.
3. Select option A.
Answer: (A) | modern |
Perpendicular motions never affect each other, so x and y solve separately. | null | phy_0313 | concept | en | Why independent axes? | [
"Perpendicular motions never affect each other, so x and y solve separately.",
"So the answer stands: Perpendicular motions never affect each other, so x and y solve separately."
] | physics | Answer: Perpendicular motions never affect each other, so x and y solve separately.
Steps:
1. Perpendicular motions never affect each other, so x and y solve separately.
2. So the answer stands: Perpendicular motions never affect each other, so x and y solve separately. | mechanics |
Voltage: 84 V. | null | phy_0314 | worked_example | en | A current of 7 A flows through 12 Ω. Compute the voltage. | [
"V = I×R.",
"V = 7 A × 12 Ω.",
"= 84 V."
] | physics | Answer: Voltage: 84 V.
Steps:
1. V = I×R.
2. V = 7 A × 12 Ω.
3. = 84 V. | electromagnetism |
Odpověď je teplota. | {
"A": "tlak",
"B": "objem",
"C": "hmotnost",
"D": "teplota"
} | phy_0315 | multiple_choice | cs | Vyber: co měří kmitání? | [
"Průměrná energie čtena.",
"Tedy: teplota.",
"Vyber možnost D."
] | physics | Answer: teplota
Steps:
1. Průměrná energie čtena.
2. Tedy: teplota.
3. Vyber možnost D.
Answer: (D) | thermodynamics |
n₁sinθ₁ rovná se n₂sinθ₂. | null | phy_0316 | concept | cs | Co je Snellův zákon? | [
"n₁sinθ₁ rovná se n₂sinθ₂.",
"Odpověď tedy platí: n₁sinθ₁ rovná se n₂sinθ₂."
] | physics | Answer: n₁sinθ₁ rovná se n₂sinθ₂.
Steps:
1. n₁sinθ₁ rovná se n₂sinθ₂.
2. Odpověď tedy platí: n₁sinθ₁ rovná se n₂sinθ₂. | optics |
3rd harmonic is 390 Hz. | {
"A": "390 Hz",
"B": "360 Hz",
"C": "420 Hz",
"D": "450 Hz"
} | phy_0317 | multiple_choice | en | A string's fundamental is 130 Hz. What is its 3rd harmonic? | [
"f3 = 3 × 130 Hz.",
"f3 = 390 Hz.",
"Select option A."
] | physics | Answer: 390 Hz
Steps:
1. f3 = 3 × 130 Hz.
2. f3 = 390 Hz.
3. Select option A.
Answer: (A) | waves |
Linked particles correlate instantly across distance, violating local realism. | null | phy_0318 | concept | en | Why entanglement? | [
"Linked particles correlate instantly across distance, violating local realism.",
"So the answer stands: Linked particles correlate instantly across distance, violating local realism."
] | physics | Answer: Linked particles correlate instantly across distance, violating local realism.
Steps:
1. Linked particles correlate instantly across distance, violating local realism.
2. So the answer stands: Linked particles correlate instantly across distance, violating local realism. | modern |
Kinetic energy is 36 J. | {
"A": "36 J",
"B": "30 J",
"C": "42 J",
"D": "48 J"
} | phy_0319 | multiple_choice | en | A 2 kg ball moves at 6 m/s. What is its kinetic energy? | [
"KE = ½×2 kg×(6 m/s)².",
"KE = 36 J.",
"Select option A."
] | physics | Answer: 36 J
Steps:
1. KE = ½×2 kg×(6 m/s)².
2. KE = 36 J.
3. Select option A.
Answer: (A) | mechanics |
Výkon: 12 W. | null | phy_0320 | worked_example | cs | Proud 2 A teče přes 3 Ω. Spočítej ztrátový výkon. | [
"P = I²×R.",
"P = (2 A)² × 3 Ω.",
"= 12 W."
] | physics | Answer: Výkon: 12 W.
Steps:
1. P = I²×R.
2. P = (2 A)² × 3 Ω.
3. = 12 W. | electromagnetism |
They turn heat flow into work between hot and cold, powering cars and plants. | null | phy_0321 | concept | en | Why heat engines? | [
"They turn heat flow into work between hot and cold, powering cars and plants.",
"So the answer stands: They turn heat flow into work between hot and cold, powering cars and plants."
] | physics | Answer: They turn heat flow into work between hot and cold, powering cars and plants.
Steps:
1. They turn heat flow into work between hot and cold, powering cars and plants.
2. So the answer stands: They turn heat flow into work between hot and cold, powering cars and plants. | thermodynamics |
Magnification is 5×. | {
"A": "4×",
"B": "6×",
"C": "7×",
"D": "5×"
} | phy_0322 | multiple_choice | en | An image forms 50 cm from a lens, object at 10 cm. What is the magnification? | [
"M = 50 cm / 10 cm.",
"M = 5×.",
"Select option D."
] | physics | Answer: 5×
Steps:
1. M = 50 cm / 10 cm.
2. M = 5×.
3. Select option D.
Answer: (D) | optics |
Distance: 2720 m. | null | phy_0323 | worked_example | en | Thunder is heard 8 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 8 s.",
"= 2720 m."
] | physics | Answer: Distance: 2720 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 8 s.
3. = 2720 m. | waves |
Mass number: 15. | null | phy_0324 | worked_example | en | A nucleus has 7 protons and 8 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 7 + 8.",
"= 15."
] | physics | Answer: Mass number: 15.
Steps:
1. A = Z+N.
2. A = 7 + 8.
3. = 15. | modern |
Speed stays fixed while direction turns, needing inward centripetal acceleration always. | null | phy_0325 | concept | en | What is uniform circular motion? | [
"Speed stays fixed while direction turns, needing inward centripetal acceleration always.",
"So the answer stands: Speed stays fixed while direction turns, needing inward centripetal acceleration always."
] | physics | Answer: Speed stays fixed while direction turns, needing inward centripetal acceleration always.
Steps:
1. Speed stays fixed while direction turns, needing inward centripetal acceleration always.
2. So the answer stands: Speed stays fixed while direction turns, needing inward centripetal acceleration always. | mechanics |
Energy: 1100 J. | null | phy_0326 | worked_example | en | A 100 W heater runs for 11 s. Compute the energy used. | [
"E = P×t.",
"E = 100 W × 11 s.",
"= 1100 J."
] | physics | Answer: Energy: 1100 J.
Steps:
1. E = P×t.
2. E = 100 W × 11 s.
3. = 1100 J. | electromagnetism |
Heat: 58604 J. | null | phy_0327 | worked_example | en | How much heat warms 2 kg of water by 7 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 7 K.",
"= 58604 J."
] | physics | Answer: Heat: 58604 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 7 K.
2. = 58604 J. | thermodynamics |
Double slits make fringe bands, measuring wavelengths precisely. | null | phy_0328 | concept | en | What is Young's experiment? | [
"Double slits make fringe bands, measuring wavelengths precisely.",
"So the answer stands: Double slits make fringe bands, measuring wavelengths precisely."
] | physics | Answer: Double slits make fringe bands, measuring wavelengths precisely.
Steps:
1. Double slits make fringe bands, measuring wavelengths precisely.
2. So the answer stands: Double slits make fringe bands, measuring wavelengths precisely. | optics |
3rd harmonic: 480 Hz. | null | phy_0329 | worked_example | en | A string's fundamental is 160 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 160 Hz.",
"= 480 Hz."
] | physics | Answer: 3rd harmonic: 480 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 160 Hz.
3. = 480 Hz. | waves |
Survivors: 1200. | null | phy_0330 | worked_example | en | A sample of 4800 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 4800 → 2400.",
"Halve: 2400 → 1200.",
"= 1200."
] | physics | Answer: Survivors: 1200.
Steps:
1. Halve: 4800 → 2400.
2. Halve: 2400 → 1200.
3. = 1200. | modern |
Momentum: 27 kg·m/s. | null | phy_0331 | worked_example | en | A mass of 9 kg moves at 3 m/s. Compute its momentum. | [
"p = m×v.",
"p = 9 kg × 3 m/s.",
"= 27 kg·m/s."
] | physics | Answer: Momentum: 27 kg·m/s.
Steps:
1. p = m×v.
2. p = 9 kg × 3 m/s.
3. = 27 kg·m/s. | mechanics |
Coiled current makes strong fields on demand, lifting scrap and ringing bells. | null | phy_0332 | concept | en | What is an electromagnet? | [
"Coiled current makes strong fields on demand, lifting scrap and ringing bells.",
"So the answer stands: Coiled current makes strong fields on demand, lifting scrap and ringing bells."
] | physics | Answer: Coiled current makes strong fields on demand, lifting scrap and ringing bells.
Steps:
1. Coiled current makes strong fields on demand, lifting scrap and ringing bells.
2. So the answer stands: Coiled current makes strong fields on demand, lifting scrap and ringing bells. | electromagnetism |
It caps engines at 1 − Tc/Th, the best any heat cycle can do. | null | phy_0333 | concept | en | What is Carnot efficiency? | [
"It caps engines at 1 − Tc/Th, the best any heat cycle can do.",
"So the answer stands: It caps engines at 1 − Tc/Th, the best any heat cycle can do."
] | physics | Answer: It caps engines at 1 − Tc/Th, the best any heat cycle can do.
Steps:
1. It caps engines at 1 − Tc/Th, the best any heat cycle can do.
2. So the answer stands: It caps engines at 1 − Tc/Th, the best any heat cycle can do. | thermodynamics |
Time: 5.3 s. | null | phy_0334 | worked_example | en | Light travels 16×10⁸ m. Compute the travel time. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 16×10⁸ / 3×10⁸ s.",
"= 5.3 s."
] | physics | Answer: Time: 5.3 s.
Steps:
1. t = d/c.
2. t = 16×10⁸ / 3×10⁸ s.
3. = 5.3 s. | optics |
Air pressure waves from 20 Hz to 20 kHz that ears hear. | null | phy_0335 | concept | en | What is sound? | [
"Air pressure waves from 20 Hz to 20 kHz that ears hear.",
"So the answer stands: Air pressure waves from 20 Hz to 20 kHz that ears hear."
] | physics | Answer: Air pressure waves from 20 Hz to 20 kHz that ears hear.
Steps:
1. Air pressure waves from 20 Hz to 20 kHz that ears hear.
2. So the answer stands: Air pressure waves from 20 Hz to 20 kHz that ears hear. | waves |
Nukleonové číslo je 4. | {
"A": "3",
"B": "5",
"C": "4",
"D": "6"
} | phy_0336 | multiple_choice | cs | Jádro má 2 protonů a 2 neutronů. Jaké je jeho nukleonové číslo? | [
"A = 2 + 2.",
"A = 4.",
"Vyber možnost C."
] | physics | Answer: 4
Steps:
1. A = 2 + 2.
2. A = 4.
3. Vyber možnost C.
Answer: (C) | modern |
Net force: 16 N. | null | phy_0337 | worked_example | en | A mass of 8 kg accelerates at 2 m/s². Compute the net force. | [
"F = m×a.",
"F = 8 kg × 2 m/s².",
"= 16 N."
] | physics | Answer: Net force: 16 N.
Steps:
1. F = m×a.
2. F = 8 kg × 2 m/s².
3. = 16 N. | mechanics |
Loop currents in fields feel twisting torques, converting electricity to motion. | null | phy_0338 | concept | en | Why motors spin? | [
"Loop currents in fields feel twisting torques, converting electricity to motion.",
"So the answer stands: Loop currents in fields feel twisting torques, converting electricity to motion."
] | physics | Answer: Loop currents in fields feel twisting torques, converting electricity to motion.
Steps:
1. Loop currents in fields feel twisting torques, converting electricity to motion.
2. So the answer stands: Loop currents in fields feel twisting torques, converting electricity to motion. | electromagnetism |
Teplo je energie proudící z tepla do chladu. | null | phy_0339 | concept | cs | Co je teplo? | [
"Teplo je energie proudící z tepla do chladu.",
"Odpověď tedy platí: Teplo je energie proudící z tepla do chladu."
] | physics | Answer: Teplo je energie proudící z tepla do chladu.
Steps:
1. Teplo je energie proudící z tepla do chladu.
2. Odpověď tedy platí: Teplo je energie proudící z tepla do chladu. | thermodynamics |
Time is 4 s. | {
"A": "4 s",
"B": "5 s",
"C": "6 s",
"D": "3 s"
} | phy_0340 | multiple_choice | en | Light travels 12×10⁸ m. How many seconds does it take? (c = 3×10⁸ m/s) | [
"t = 12×10⁸ m / 3×10⁸ m/s.",
"t = 4 s.",
"Select option A."
] | physics | Answer: 4 s
Steps:
1. t = 12×10⁸ m / 3×10⁸ m/s.
2. t = 4 s.
3. Select option A.
Answer: (A) | optics |
3. harmonická: 330 Hz. | null | phy_0341 | worked_example | cs | Základ struny je 110 Hz. Spočítej její 3. harmonickou. | [
"f3 = 3×f1.",
"f3 = 3 × 110 Hz.",
"= 330 Hz."
] | physics | Answer: 3. harmonická: 330 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 110 Hz.
3. = 330 Hz. | waves |
Lines: 36. | null | phy_0342 | worked_example | en | An atom is excited to level n = 9. Count the spectral lines it can emit. | [
"Pairs: 9×8/2.",
"= 72/2.",
"= 36."
] | physics | Answer: Lines: 36.
Steps:
1. Pairs: 9×8/2.
2. = 72/2.
3. = 36. | modern |
Work: 140 J. | null | phy_0343 | worked_example | en | A force of 35 N pushes 4 m. Compute the work done. | [
"W = F×d.",
"W = 35 N × 4 m.",
"= 140 J."
] | physics | Answer: Work: 140 J.
Steps:
1. W = F×d.
2. W = 35 N × 4 m.
3. = 140 J. | mechanics |
Napětí: 24 V. | null | phy_0344 | worked_example | cs | Proud 2 A teče přes 12 Ω. Spočítej napětí. | [
"U = I×R.",
"U = 2 A × 12 Ω.",
"= 24 V."
] | physics | Answer: Napětí: 24 V.
Steps:
1. U = I×R.
2. U = 2 A × 12 Ω.
3. = 24 V. | electromagnetism |
They pump heat uphill with work input, cooling insides below room. | null | phy_0345 | concept | en | Why refrigerators? | [
"They pump heat uphill with work input, cooling insides below room.",
"So the answer stands: They pump heat uphill with work input, cooling insides below room."
] | physics | Answer: They pump heat uphill with work input, cooling insides below room.
Steps:
1. They pump heat uphill with work input, cooling insides below room.
2. So the answer stands: They pump heat uphill with work input, cooling insides below room. | thermodynamics |
Reflections from both film faces interfere, colouring bubbles and oil. | null | phy_0346 | concept | en | Why thin-film colours? | [
"Reflections from both film faces interfere, colouring bubbles and oil.",
"So the answer stands: Reflections from both film faces interfere, colouring bubbles and oil."
] | physics | Answer: Reflections from both film faces interfere, colouring bubbles and oil.
Steps:
1. Reflections from both film faces interfere, colouring bubbles and oil.
2. So the answer stands: Reflections from both film faces interfere, colouring bubbles and oil. | optics |
The answer is Frequency. | {
"A": "Amplitude",
"B": "Frequency",
"C": "Phase",
"D": "Speed"
} | phy_0347 | multiple_choice | en | Choose: what sets pitch? | [
"Hertz counted.",
"So: Frequency.",
"Select option B."
] | physics | Answer: Frequency
Steps:
1. Hertz counted.
2. So: Frequency.
3. Select option B.
Answer: (B) | waves |
Mass number: 17. | null | phy_0348 | worked_example | en | A nucleus has 8 protons and 9 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 8 + 9.",
"= 17."
] | physics | Answer: Mass number: 17.
Steps:
1. A = Z+N.
2. A = 8 + 9.
3. = 17. | modern |
The answer is Action-reaction. | {
"A": "Cause-delay",
"B": "Action-reaction",
"C": "Push-rest",
"D": "Pull-sleep"
} | phy_0349 | multiple_choice | en | Choose: what pairs forces? | [
"Third law pairs.",
"So: Action-reaction.",
"Select option B."
] | physics | Answer: Action-reaction
Steps:
1. Third law pairs.
2. So: Action-reaction.
3. Select option B.
Answer: (B) | mechanics |
Odpověď je náboj. | {
"A": "hmotnost",
"B": "spin",
"C": "barva",
"D": "náboj"
} | phy_0350 | multiple_choice | cs | Vyber: co přitahuje opačné? | [
"Plus potkává minus.",
"Tedy: náboj.",
"Vyber možnost D."
] | physics | Answer: náboj
Steps:
1. Plus potkává minus.
2. Tedy: náboj.
3. Vyber možnost D.
Answer: (D) | electromagnetism |
Power: 110 W. | null | phy_0351 | worked_example | en | An engine does 1100 J of work in 10 s. Compute its power. | [
"P = W/t.",
"P = 1100 J / 10 s.",
"= 110 W."
] | physics | Answer: Power: 110 W.
Steps:
1. P = W/t.
2. P = 1100 J / 10 s.
3. = 110 W. | thermodynamics |
Apparent depth is 50 cm. | {
"A": "45 cm",
"B": "50 cm",
"C": "55 cm",
"D": "60 cm"
} | phy_0352 | multiple_choice | en | An object sits 75 cm deep in glass (n = 1.5). What is the apparent depth? | [
"d' = 75 cm / 1.5.",
"d' = 50 cm.",
"Select option B."
] | physics | Answer: 50 cm
Steps:
1. d' = 75 cm / 1.5.
2. d' = 50 cm.
3. Select option B.
Answer: (B) | optics |
Speed: 1650 m/s. | null | phy_0353 | worked_example | en | A string wave has f = 550 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 550 Hz × 3 m.",
"= 1650 m/s."
] | physics | Answer: Speed: 1650 m/s.
Steps:
1. v = f×λ.
2. v = 550 Hz × 3 m.
3. = 1650 m/s. | waves |
Single particles build interference bands, proving self-wave nature. | null | phy_0354 | concept | en | What is the double slit? | [
"Single particles build interference bands, proving self-wave nature.",
"So the answer stands: Single particles build interference bands, proving self-wave nature."
] | physics | Answer: Single particles build interference bands, proving self-wave nature.
Steps:
1. Single particles build interference bands, proving self-wave nature.
2. So the answer stands: Single particles build interference bands, proving self-wave nature. | modern |
Inward net force bends paths into circles, from string tension to planetary gravity. | null | phy_0355 | concept | en | Why centripetal force? | [
"Inward net force bends paths into circles, from string tension to planetary gravity.",
"So the answer stands: Inward net force bends paths into circles, from string tension to planetary gravity."
] | physics | Answer: Inward net force bends paths into circles, from string tension to planetary gravity.
Steps:
1. Inward net force bends paths into circles, from string tension to planetary gravity.
2. So the answer stands: Inward net force bends paths into circles, from string tension to planetary gravity. | mechanics |
Napětí je energie na náboj ve voltech. | null | phy_0356 | concept | cs | Co je napětí? | [
"Napětí je energie na náboj ve voltech.",
"Odpověď tedy platí: Napětí je energie na náboj ve voltech."
] | physics | Answer: Napětí je energie na náboj ve voltech.
Steps:
1. Napětí je energie na náboj ve voltech.
2. Odpověď tedy platí: Napětí je energie na náboj ve voltech. | electromagnetism |
The answer is Heat. | {
"A": "Work",
"B": "Heat",
"C": "Charge",
"D": "Light"
} | phy_0357 | multiple_choice | en | Choose: what flows hot to cold? | [
"Joules moved.",
"So: Heat.",
"Select option B."
] | physics | Answer: Heat
Steps:
1. Joules moved.
2. So: Heat.
3. Select option B.
Answer: (B) | thermodynamics |
Apparent depth: 70 cm. | null | phy_0358 | worked_example | en | An object sits 105 cm deep in glass (n = 1.5). Compute the apparent depth. | [
"d' = d/n.",
"d' = 105 cm / 1.5.",
"= 70 cm."
] | physics | Answer: Apparent depth: 70 cm.
Steps:
1. d' = d/n.
2. d' = 105 cm / 1.5.
3. = 70 cm. | optics |
Air molecules pass hits at about 343 m/s, faster when warm. | null | phy_0359 | concept | en | Why speed of sound? | [
"Air molecules pass hits at about 343 m/s, faster when warm.",
"So the answer stands: Air molecules pass hits at about 343 m/s, faster when warm."
] | physics | Answer: Air molecules pass hits at about 343 m/s, faster when warm.
Steps:
1. Air molecules pass hits at about 343 m/s, faster when warm.
2. So the answer stands: Air molecules pass hits at about 343 m/s, faster when warm. | waves |
Survivors: 1400. | null | phy_0360 | worked_example | en | A sample of 5600 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 5600 → 2800.",
"Halve: 2800 → 1400.",
"= 1400."
] | physics | Answer: Survivors: 1400.
Steps:
1. Halve: 5600 → 2800.
2. Halve: 2800 → 1400.
3. = 1400. | modern |
Work is force times distance along motion, transferring energy measured in joules. | null | phy_0361 | concept | en | What is work? | [
"Work is force times distance along motion, transferring energy measured in joules.",
"So the answer stands: Work is force times distance along motion, transferring energy measured in joules."
] | physics | Answer: Work is force times distance along motion, transferring energy measured in joules.
Steps:
1. Work is force times distance along motion, transferring energy measured in joules.
2. So the answer stands: Work is force times distance along motion, transferring energy measured in joules. | mechanics |
Voltage is 20 V. | {
"A": "15 V",
"B": "25 V",
"C": "20 V",
"D": "30 V"
} | phy_0362 | multiple_choice | en | A current of 4 A flows through 5 Ω. What is the voltage? | [
"V = 4 A × 5 Ω.",
"V = 20 V.",
"Select option C."
] | physics | Answer: 20 V
Steps:
1. V = 4 A × 5 Ω.
2. V = 20 V.
3. Select option C.
Answer: (C) | electromagnetism |
Temperature: 295 K. | null | phy_0363 | worked_example | en | Temperature is 22 °C. Convert it to kelvin. | [
"Add 273.",
"22 + 273.",
"= 295 K."
] | physics | Answer: Temperature: 295 K.
Steps:
1. Add 273.
2. 22 + 273.
3. = 295 K. | thermodynamics |
Čas: 2,3 s. | null | phy_0364 | worked_example | cs | Světlo letí 7×10⁸ m. Spočítej dobu letu. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 7×10⁸ / 3×10⁸ s.",
"= 2,3 s."
] | physics | Answer: Čas: 2,3 s.
Steps:
1. t = d/c.
2. t = 7×10⁸ / 3×10⁸ s.
3. = 2,3 s. | optics |
Rychlost rovná se cyklům krát délka. | null | phy_0365 | concept | cs | Proč v rovná se fλ? | [
"Rychlost rovná se cyklům krát délka.",
"Odpověď tedy platí: Rychlost rovná se cyklům krát délka."
] | physics | Answer: Rychlost rovná se cyklům krát délka.
Steps:
1. Rychlost rovná se cyklům krát délka.
2. Odpověď tedy platí: Rychlost rovná se cyklům krát délka. | waves |
Lines: 45. | null | phy_0366 | worked_example | en | An atom is excited to level n = 10. Count the spectral lines it can emit. | [
"Pairs: 10×9/2.",
"= 90/2.",
"= 45."
] | physics | Answer: Lines: 45.
Steps:
1. Pairs: 10×9/2.
2. = 90/2.
3. = 45. | modern |
Moving mass carries ½mv² of energy, freed in braking or collisions. | null | phy_0367 | concept | en | Why kinetic energy? | [
"Moving mass carries ½mv² of energy, freed in braking or collisions.",
"So the answer stands: Moving mass carries ½mv² of energy, freed in braking or collisions."
] | physics | Answer: Moving mass carries ½mv² of energy, freed in braking or collisions.
Steps:
1. Moving mass carries ½mv² of energy, freed in braking or collisions.
2. So the answer stands: Moving mass carries ½mv² of energy, freed in braking or collisions. | mechanics |
Power: 192 W. | null | phy_0368 | worked_example | en | A current of 8 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (8 A)² × 3 Ω.",
"= 192 W."
] | physics | Answer: Power: 192 W.
Steps:
1. P = I²×R.
2. P = (8 A)² × 3 Ω.
3. = 192 W. | electromagnetism |
Teplo: 16744 J. | null | phy_0369 | worked_example | cs | Kolik tepla ohřeje 2 kg vody o 2 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 2 K.",
"= 16744 J."
] | physics | Answer: Teplo: 16744 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 2 K.
2. = 16744 J. | thermodynamics |
Filtering oscillation direction cuts glare, used in sunglasses and screens. | null | phy_0370 | concept | en | What is polarization? | [
"Filtering oscillation direction cuts glare, used in sunglasses and screens.",
"So the answer stands: Filtering oscillation direction cuts glare, used in sunglasses and screens."
] | physics | Answer: Filtering oscillation direction cuts glare, used in sunglasses and screens.
Steps:
1. Filtering oscillation direction cuts glare, used in sunglasses and screens.
2. So the answer stands: Filtering oscillation direction cuts glare, used in sunglasses and screens. | optics |
Distance: 3060 m. | null | phy_0371 | worked_example | en | Thunder is heard 9 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 9 s.",
"= 3060 m."
] | physics | Answer: Distance: 3060 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 9 s.
3. = 3060 m. | waves |
Mass number: 19. | null | phy_0372 | worked_example | en | A nucleus has 9 protons and 10 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 9 + 10.",
"= 19."
] | physics | Answer: Mass number: 19.
Steps:
1. A = Z+N.
2. A = 9 + 10.
3. = 19. | modern |
The answer is Momentum. | {
"A": "Speed",
"B": "Heat",
"C": "Momentum",
"D": "Sound"
} | phy_0373 | multiple_choice | en | Choose: what persists in collisions? | [
"Sum conserved.",
"So: Momentum.",
"Select option C."
] | physics | Answer: Momentum
Steps:
1. Sum conserved.
2. So: Momentum.
3. Select option C.
Answer: (C) | mechanics |
Changing magnetic flux drives voltage in coils, the generator principle. | null | phy_0374 | concept | en | What is induction? | [
"Changing magnetic flux drives voltage in coils, the generator principle.",
"So the answer stands: Changing magnetic flux drives voltage in coils, the generator principle."
] | physics | Answer: Changing magnetic flux drives voltage in coils, the generator principle.
Steps:
1. Changing magnetic flux drives voltage in coils, the generator principle.
2. So the answer stands: Changing magnetic flux drives voltage in coils, the generator principle. | electromagnetism |
Je energie na hmotnost a stupeň, voda ji má vysokou. | null | phy_0375 | concept | cs | Proč měrná kapacita? | [
"Je energie na hmotnost a stupeň, voda ji má vysokou.",
"Odpověď tedy platí: Je energie na hmotnost a stupeň, voda ji má vysokou."
] | physics | Answer: Je energie na hmotnost a stupeň, voda ji má vysokou.
Steps:
1. Je energie na hmotnost a stupeň, voda ji má vysokou.
2. Odpověď tedy platí: Je energie na hmotnost a stupeň, voda ji má vysokou. | thermodynamics |
Za mezním úhlem se vše odráží uvnitř. | null | phy_0376 | concept | cs | Proč úplný odraz? | [
"Za mezním úhlem se vše odráží uvnitř.",
"Odpověď tedy platí: Za mezním úhlem se vše odráží uvnitř."
] | physics | Answer: Za mezním úhlem se vše odráží uvnitř.
Steps:
1. Za mezním úhlem se vše odráží uvnitř.
2. Odpověď tedy platí: Za mezním úhlem se vše odráží uvnitř. | optics |
The answer is Ultrasound. | {
"A": "X-ray",
"B": "Gamma ray",
"C": "Ultrasound",
"D": "Microwave"
} | phy_0377 | multiple_choice | en | Choose: what images babies? | [
"Echoes mapped.",
"So: Ultrasound.",
"Select option C."
] | physics | Answer: Ultrasound
Steps:
1. Echoes mapped.
2. So: Ultrasound.
3. Select option C.
Answer: (C) | waves |
Survivors: 1600. | null | phy_0378 | worked_example | en | A sample of 6400 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 6400 → 3200.",
"Halve: 3200 → 1600.",
"= 1600."
] | physics | Answer: Survivors: 1600.
Steps:
1. Halve: 6400 → 3200.
2. Halve: 3200 → 1600.
3. = 1600. | modern |
Net force is 15 N. | {
"A": "12 N",
"B": "18 N",
"C": "21 N",
"D": "15 N"
} | phy_0379 | multiple_choice | en | A mass of 5 kg accelerates at 3 m/s². What is the net force? | [
"F = 5 kg × 3 m/s².",
"F = 15 N.",
"Select option D."
] | physics | Answer: 15 N
Steps:
1. F = 5 kg × 3 m/s².
2. F = 15 N.
3. Select option D.
Answer: (D) | mechanics |
Power is 60 W. | {
"A": "48 W",
"B": "72 W",
"C": "84 W",
"D": "60 W"
} | phy_0380 | multiple_choice | en | A bulb runs at 12 V drawing 5 A. What is its power? | [
"P = 12 V × 5 A.",
"P = 60 W.",
"Select option D."
] | physics | Answer: 60 W
Steps:
1. P = 12 V × 5 A.
2. P = 60 W.
3. Select option D.
Answer: (D) | electromagnetism |
Zahřáté částice se rozestupují. | null | phy_0381 | concept | cs | Co je teplotní roztažnost? | [
"Zahřáté částice se rozestupují.",
"Odpověď tedy platí: Zahřáté částice se rozestupují."
] | physics | Answer: Zahřáté částice se rozestupují.
Steps:
1. Zahřáté částice se rozestupují.
2. Odpověď tedy platí: Zahřáté částice se rozestupují. | thermodynamics |
Magnification: 8×. | null | phy_0382 | worked_example | en | An image forms 80 cm from a lens, object at 10 cm. Compute the magnification. | [
"M = di/do.",
"M = 80 cm / 10 cm.",
"= 8×."
] | physics | Answer: Magnification: 8×.
Steps:
1. M = di/do.
2. M = 80 cm / 10 cm.
3. = 8×. | optics |
3rd harmonic: 510 Hz. | null | phy_0383 | worked_example | en | A string's fundamental is 170 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 170 Hz.",
"= 510 Hz."
] | physics | Answer: 3rd harmonic: 510 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 170 Hz.
3. = 510 Hz. | waves |
The answer is Black hole. | {
"A": "White dwarf",
"B": "Black hole",
"C": "Red giant",
"D": "Blue note"
} | phy_0384 | multiple_choice | en | Choose: what traps light? | [
"Horizon seals.",
"So: Black hole.",
"Select option B."
] | physics | Answer: Black hole
Steps:
1. Horizon seals.
2. So: Black hole.
3. Select option B.
Answer: (B) | modern |
Hybnost: 21 kg·m/s. | null | phy_0385 | worked_example | cs | Těleso 7 kg se pohybuje 3 m/s. Spočítej jeho hybnost. | [
"p = m×v.",
"p = 7 kg × 3 m/s.",
"= 21 kg·m/s."
] | physics | Answer: Hybnost: 21 kg·m/s.
Steps:
1. p = m×v.
2. p = 7 kg × 3 m/s.
3. = 21 kg·m/s. | mechanics |
Charge is 80 C. | {
"A": "80 C",
"B": "60 C",
"C": "100 C",
"D": "120 C"
} | phy_0386 | multiple_choice | en | A current of 4 A flows for 20 s. How much charge passes? | [
"Q = 4 A × 20 s.",
"Q = 80 C.",
"Select option A."
] | physics | Answer: 80 C
Steps:
1. Q = 4 A × 20 s.
2. Q = 80 C.
3. Select option A.
Answer: (A) | electromagnetism |
Entropy counts microscopic disorder, always growing in isolated change. | null | phy_0387 | concept | en | What is entropy? | [
"Entropy counts microscopic disorder, always growing in isolated change.",
"So the answer stands: Entropy counts microscopic disorder, always growing in isolated change."
] | physics | Answer: Entropy counts microscopic disorder, always growing in isolated change.
Steps:
1. Entropy counts microscopic disorder, always growing in isolated change.
2. So the answer stands: Entropy counts microscopic disorder, always growing in isolated change. | thermodynamics |
Reflected light polarizes fully at one angle, exploited by photographers. | null | phy_0388 | concept | en | Why Brewster's angle? | [
"Reflected light polarizes fully at one angle, exploited by photographers.",
"So the answer stands: Reflected light polarizes fully at one angle, exploited by photographers."
] | physics | Answer: Reflected light polarizes fully at one angle, exploited by photographers.
Steps:
1. Reflected light polarizes fully at one angle, exploited by photographers.
2. So the answer stands: Reflected light polarizes fully at one angle, exploited by photographers. | optics |
Speed is 500 m/s. | {
"A": "450 m/s",
"B": "550 m/s",
"C": "600 m/s",
"D": "500 m/s"
} | phy_0389 | multiple_choice | en | A string wave has f = 250 Hz and λ = 2 m. What is its speed? | [
"v = 250 Hz × 2 m.",
"v = 500 m/s.",
"Select option D."
] | physics | Answer: 500 m/s
Steps:
1. v = 250 Hz × 2 m.
2. v = 500 m/s.
3. Select option D.
Answer: (D) | waves |
The answer is Higgs field. | {
"A": "Corn field",
"B": "Mine field",
"C": "Higgs field",
"D": "Playing field"
} | phy_0390 | multiple_choice | en | Choose: what drags mass? | [
"Found in 2012.",
"So: Higgs field.",
"Select option C."
] | physics | Answer: Higgs field
Steps:
1. Found in 2012.
2. So: Higgs field.
3. Select option C.
Answer: (C) | modern |
Momentum: 30 kg·m/s. | null | phy_0391 | worked_example | en | A mass of 10 kg moves at 3 m/s. Compute its momentum. | [
"p = m×v.",
"p = 10 kg × 3 m/s.",
"= 30 kg·m/s."
] | physics | Answer: Momentum: 30 kg·m/s.
Steps:
1. p = m×v.
2. p = 10 kg × 3 m/s.
3. = 30 kg·m/s. | mechanics |
The answer is Ohm's law. | {
"A": "Hooke's law",
"B": "Ohm's law",
"C": "Boyle's law",
"D": "Snell's law"
} | phy_0392 | multiple_choice | en | Choose: what links V, I, R? | [
"V equals IR.",
"So: Ohm's law.",
"Select option B."
] | physics | Answer: Ohm's law
Steps:
1. V equals IR.
2. So: Ohm's law.
3. Select option B.
Answer: (B) | electromagnetism |
Motion's minimum forbids colder, and the third law bars ever reaching it. | null | phy_0393 | concept | en | Why absolute zero? | [
"Motion's minimum forbids colder, and the third law bars ever reaching it.",
"So the answer stands: Motion's minimum forbids colder, and the third law bars ever reaching it."
] | physics | Answer: Motion's minimum forbids colder, and the third law bars ever reaching it.
Steps:
1. Motion's minimum forbids colder, and the third law bars ever reaching it.
2. So the answer stands: Motion's minimum forbids colder, and the third law bars ever reaching it. | thermodynamics |
Time: 6.3 s. | null | phy_0394 | worked_example | en | Light travels 19×10⁸ m. Compute the travel time. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 19×10⁸ / 3×10⁸ s.",
"= 6.3 s."
] | physics | Answer: Time: 6.3 s.
Steps:
1. t = d/c.
2. t = 19×10⁸ / 3×10⁸ s.
3. = 6.3 s. | optics |
Speed: 1800 m/s. | null | phy_0395 | worked_example | en | A string wave has f = 600 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 600 Hz × 3 m.",
"= 1800 m/s."
] | physics | Answer: Speed: 1800 m/s.
Steps:
1. v = f×λ.
2. v = 600 Hz × 3 m.
3. = 1800 m/s. | waves |
400 atoms remain. | {
"A": "350",
"B": "450",
"C": "500",
"D": "400"
} | phy_0396 | multiple_choice | en | A sample of 1600 atoms undergoes 2 half-lives. How many remain? | [
"Halve twice: 1600 → 800 → 400.",
"Left: 400.",
"Select option D."
] | physics | Answer: 400
Steps:
1. Halve twice: 1600 → 800 → 400.
2. Left: 400.
3. Select option D.
Answer: (D) | modern |
Net force: 18 N. | null | phy_0397 | worked_example | en | A mass of 9 kg accelerates at 2 m/s². Compute the net force. | [
"F = m×a.",
"F = 9 kg × 2 m/s².",
"= 18 N."
] | physics | Answer: Net force: 18 N.
Steps:
1. F = m×a.
2. F = 9 kg × 2 m/s².
3. = 18 N. | mechanics |
Shared flux scales voltage by turns ratio, shipping power high and safe. | null | phy_0398 | concept | en | Why transformers? | [
"Shared flux scales voltage by turns ratio, shipping power high and safe.",
"So the answer stands: Shared flux scales voltage by turns ratio, shipping power high and safe."
] | physics | Answer: Shared flux scales voltage by turns ratio, shipping power high and safe.
Steps:
1. Shared flux scales voltage by turns ratio, shipping power high and safe.
2. So the answer stands: Shared flux scales voltage by turns ratio, shipping power high and safe. | electromagnetism |
Point particles with elastic hits obey pV = nRT simply and usefully. | null | phy_0399 | concept | en | What is an ideal gas? | [
"Point particles with elastic hits obey pV = nRT simply and usefully.",
"So the answer stands: Point particles with elastic hits obey pV = nRT simply and usefully."
] | physics | Answer: Point particles with elastic hits obey pV = nRT simply and usefully.
Steps:
1. Point particles with elastic hits obey pV = nRT simply and usefully.
2. So the answer stands: Point particles with elastic hits obey pV = nRT simply and usefully. | thermodynamics |
Zdánlivá hloubka: 40 cm. | null | phy_0400 | worked_example | cs | Předmět leží 60 cm hluboko ve skle (n = 1,5). Spočítej zdánlivou hloubku. | [
"d' = d/n.",
"d' = 60 cm / 1,5.",
"= 40 cm."
] | physics | Answer: Zdánlivá hloubka: 40 cm.
Steps:
1. d' = d/n.
2. d' = 60 cm / 1,5.
3. = 40 cm. | optics |
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