answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
3rd harmonic: 330 Hz. | null | phy_0101 | worked_example | en | A string's fundamental is 110 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 110 Hz.",
"= 330 Hz."
] | physics | Answer: 3rd harmonic: 330 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 110 Hz.
3. = 330 Hz. | waves |
Mass number: 9. | null | phy_0102 | worked_example | en | A nucleus has 4 protons and 5 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 4 + 5.",
"= 9."
] | physics | Answer: Mass number: 9.
Steps:
1. A = Z+N.
2. A = 4 + 5.
3. = 9. | modern |
Work: 60 J. | null | phy_0103 | worked_example | en | A force of 15 N pushes 4 m. Compute the work done. | [
"W = F×d.",
"W = 15 N × 4 m.",
"= 60 J."
] | physics | Answer: Work: 60 J.
Steps:
1. W = F×d.
2. W = 15 N × 4 m.
3. = 60 J. | mechanics |
Power is 36 W. | {
"A": "24 W",
"B": "36 W",
"C": "48 W",
"D": "60 W"
} | phy_0104 | multiple_choice | en | A bulb runs at 12 V drawing 3 A. What is its power? | [
"P = 12 V × 3 A.",
"P = 36 W.",
"Select option B."
] | physics | Answer: 36 W
Steps:
1. P = 12 V × 3 A.
2. P = 36 W.
3. Select option B.
Answer: (B) | electromagnetism |
Teplo: 8372 J. | null | phy_0105 | worked_example | cs | Kolik tepla ohřeje 2 kg vody o 1 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 1 K.",
"= 8372 J."
] | physics | Answer: Teplo: 8372 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 1 K.
2. = 8372 J. | thermodynamics |
Magnification is 3×. | {
"A": "2×",
"B": "3×",
"C": "4×",
"D": "5×"
} | phy_0106 | multiple_choice | en | An image forms 30 cm from a lens, object at 10 cm. What is the magnification? | [
"M = 30 cm / 10 cm.",
"M = 3×.",
"Select option B."
] | physics | Answer: 3×
Steps:
1. M = 30 cm / 10 cm.
2. M = 3×.
3. Select option B.
Answer: (B) | optics |
The answer is Wave. | {
"A": "Wind",
"B": "River",
"C": "Truck",
"D": "Wave"
} | phy_0107 | multiple_choice | en | Choose: what carries without matter? | [
"Energy travels.",
"So: Wave.",
"Select option D."
] | physics | Answer: Wave
Steps:
1. Energy travels.
2. So: Wave.
3. Select option D.
Answer: (D) | waves |
Pohyb zakřivuje čas a prostor a drží c pevné. | null | phy_0108 | concept | cs | Co je relativita? | [
"Pohyb zakřivuje čas a prostor a drží c pevné.",
"Odpověď tedy platí: Pohyb zakřivuje čas a prostor a drží c pevné."
] | physics | Answer: Pohyb zakřivuje čas a prostor a drží c pevné.
Steps:
1. Pohyb zakřivuje čas a prostor a drží c pevné.
2. Odpověď tedy platí: Pohyb zakřivuje čas a prostor a drží c pevné. | modern |
Momentum: 18 kg·m/s. | null | phy_0109 | worked_example | en | A mass of 6 kg moves at 3 m/s. Compute its momentum. | [
"p = m×v.",
"p = 6 kg × 3 m/s.",
"= 18 kg·m/s."
] | physics | Answer: Momentum: 18 kg·m/s.
Steps:
1. p = m×v.
2. p = 6 kg × 3 m/s.
3. = 18 kg·m/s. | mechanics |
Napětí je 10 V. | {
"A": "10 V",
"B": "5 V",
"C": "15 V",
"D": "20 V"
} | phy_0110 | multiple_choice | cs | Proud 2 A teče přes 5 Ω. Jaké je napětí? | [
"U = 2 A × 5 Ω.",
"U = 10 V.",
"Vyber možnost A."
] | physics | Answer: 10 V
Steps:
1. U = 2 A × 5 Ω.
2. U = 10 V.
3. Vyber možnost A.
Answer: (A) | electromagnetism |
Colliding particles pass energy along solids, fastest through metals. | null | phy_0111 | concept | en | Why conduction? | [
"Colliding particles pass energy along solids, fastest through metals.",
"So the answer stands: Colliding particles pass energy along solids, fastest through metals."
] | physics | Answer: Colliding particles pass energy along solids, fastest through metals.
Steps:
1. Colliding particles pass energy along solids, fastest through metals.
2. So the answer stands: Colliding particles pass energy along solids, fastest through metals. | thermodynamics |
Time is 2 s. | {
"A": "3 s",
"B": "4 s",
"C": "2 s",
"D": "1 s"
} | phy_0112 | multiple_choice | en | Light travels 6×10⁸ m. How many seconds does it take? (c = 3×10⁸ m/s) | [
"t = 6×10⁸ m / 3×10⁸ m/s.",
"t = 2 s.",
"Select option C."
] | physics | Answer: 2 s
Steps:
1. t = 6×10⁸ m / 3×10⁸ m/s.
2. t = 2 s.
3. Select option C.
Answer: (C) | optics |
Speed: 900 m/s. | null | phy_0113 | worked_example | en | A string wave has f = 300 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 300 Hz × 3 m.",
"= 900 m/s."
] | physics | Answer: Speed: 900 m/s.
Steps:
1. v = f×λ.
2. v = 300 Hz × 3 m.
3. = 900 m/s. | waves |
The answer is Fission. | {
"A": "Fission",
"B": "Fusion",
"C": "Fashion",
"D": "Fiction"
} | phy_0114 | multiple_choice | en | Choose: what splits heavy? | [
"Reactors chained.",
"So: Fission.",
"Select option A."
] | physics | Answer: Fission
Steps:
1. Reactors chained.
2. So: Fission.
3. Select option A.
Answer: (A) | modern |
Rychlost je 10 m/s. | {
"A": "9 m/s",
"B": "10 m/s",
"C": "11 m/s",
"D": "12 m/s"
} | phy_0115 | multiple_choice | cs | Auto ujede 100 m za 10 s. Jaká je jeho rychlost? | [
"v = 100 m / 10 s.",
"v = 10 m/s.",
"Vyber možnost B."
] | physics | Answer: 10 m/s
Steps:
1. v = 100 m / 10 s.
2. v = 10 m/s.
3. Vyber možnost B.
Answer: (B) | mechanics |
Charge is 40 C. | {
"A": "20 C",
"B": "60 C",
"C": "40 C",
"D": "80 C"
} | phy_0116 | multiple_choice | en | A current of 4 A flows for 10 s. How much charge passes? | [
"Q = 4 A × 10 s.",
"Q = 40 C.",
"Select option C."
] | physics | Answer: 40 C
Steps:
1. Q = 4 A × 10 s.
2. Q = 40 C.
3. Select option C.
Answer: (C) | electromagnetism |
Flowing fluids carry heat in currents, from radiators to weather. | null | phy_0117 | concept | en | What is convection? | [
"Flowing fluids carry heat in currents, from radiators to weather.",
"So the answer stands: Flowing fluids carry heat in currents, from radiators to weather."
] | physics | Answer: Flowing fluids carry heat in currents, from radiators to weather.
Steps:
1. Flowing fluids carry heat in currents, from radiators to weather.
2. So the answer stands: Flowing fluids carry heat in currents, from radiators to weather. | thermodynamics |
Apparent depth is 30 cm. | {
"A": "25 cm",
"B": "35 cm",
"C": "40 cm",
"D": "30 cm"
} | phy_0118 | multiple_choice | en | An object sits 45 cm deep in glass (n = 1.5). What is the apparent depth? | [
"d' = 45 cm / 1.5.",
"d' = 30 cm.",
"Select option D."
] | physics | Answer: 30 cm
Steps:
1. d' = 45 cm / 1.5.
2. d' = 30 cm.
3. Select option D.
Answer: (D) | optics |
Distance: 1360 m. | null | phy_0119 | worked_example | en | Thunder is heard 4 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 4 s.",
"= 1360 m."
] | physics | Answer: Distance: 1360 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 4 s.
3. = 1360 m. | waves |
Gravity is curved spacetime guiding falling paths, bending starlight. | null | phy_0120 | concept | en | Why general relativity? | [
"Gravity is curved spacetime guiding falling paths, bending starlight.",
"So the answer stands: Gravity is curved spacetime guiding falling paths, bending starlight."
] | physics | Answer: Gravity is curved spacetime guiding falling paths, bending starlight.
Steps:
1. Gravity is curved spacetime guiding falling paths, bending starlight.
2. So the answer stands: Gravity is curved spacetime guiding falling paths, bending starlight. | modern |
Práce: 40 J. | null | phy_0121 | worked_example | cs | Síla 10 N tlačí na dráze 4 m. Spočítej vykonanou práci. | [
"W = F×d.",
"W = 10 N × 4 m.",
"= 40 J."
] | physics | Answer: Práce: 40 J.
Steps:
1. W = F×d.
2. W = 10 N × 4 m.
3. = 40 J. | mechanics |
The answer is Charge. | {
"A": "Mass",
"B": "Spin",
"C": "Color",
"D": "Charge"
} | phy_0122 | multiple_choice | en | Choose: what attracts opposites? | [
"Plus meets minus.",
"So: Charge.",
"Select option D."
] | physics | Answer: Charge
Steps:
1. Plus meets minus.
2. So: Charge.
3. Select option D.
Answer: (D) | electromagnetism |
Temperature: 290 K. | null | phy_0123 | worked_example | en | Temperature is 17 °C. Convert it to kelvin. | [
"Add 273.",
"17 + 273.",
"= 290 K."
] | physics | Answer: Temperature: 290 K.
Steps:
1. Add 273.
2. 17 + 273.
3. = 290 K. | thermodynamics |
Změna rychlosti ohýbá paprsky podle Snellova zákona. | null | phy_0124 | concept | cs | Proč lom? | [
"Změna rychlosti ohýbá paprsky podle Snellova zákona.",
"Odpověď tedy platí: Změna rychlosti ohýbá paprsky podle Snellova zákona."
] | physics | Answer: Změna rychlosti ohýbá paprsky podle Snellova zákona.
Steps:
1. Změna rychlosti ohýbá paprsky podle Snellova zákona.
2. Odpověď tedy platí: Změna rychlosti ohýbá paprsky podle Snellova zákona. | optics |
Rychlost: 750 m/s. | null | phy_0125 | worked_example | cs | Vlna na struně má f = 250 Hz a λ = 3 m. Spočítej její rychlost. | [
"v = f×λ.",
"v = 250 Hz × 3 m.",
"= 750 m/s."
] | physics | Answer: Rychlost: 750 m/s.
Steps:
1. v = f×λ.
2. v = 250 Hz × 3 m.
3. = 750 m/s. | waves |
200 atoms remain. | {
"A": "150",
"B": "200",
"C": "250",
"D": "300"
} | phy_0126 | multiple_choice | en | A sample of 800 atoms undergoes 2 half-lives. How many remain? | [
"Halve twice: 800 → 400 → 200.",
"Left: 200.",
"Select option B."
] | physics | Answer: 200
Steps:
1. Halve twice: 800 → 400 → 200.
2. Left: 200.
3. Select option B.
Answer: (B) | modern |
Speed is 11 m/s. | {
"A": "10 m/s",
"B": "12 m/s",
"C": "11 m/s",
"D": "13 m/s"
} | phy_0127 | multiple_choice | en | A car travels 110 m in 10 s. What is its speed? | [
"v = 110 m / 10 s.",
"v = 11 m/s.",
"Select option C."
] | physics | Answer: 11 m/s
Steps:
1. v = 110 m / 10 s.
2. v = 11 m/s.
3. Select option C.
Answer: (C) | mechanics |
Power: 48 W. | null | phy_0128 | worked_example | en | A current of 4 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (4 A)² × 3 Ω.",
"= 48 W."
] | physics | Answer: Power: 48 W.
Steps:
1. P = I²×R.
2. P = (4 A)² × 3 Ω.
3. = 48 W. | electromagnetism |
Výkon: 50 W. | null | phy_0129 | worked_example | cs | Motor vykoná 500 J práce za 10 s. Spočítej jeho výkon. | [
"P = W/t.",
"P = 500 J / 10 s.",
"= 50 W."
] | physics | Answer: Výkon: 50 W.
Steps:
1. P = W/t.
2. P = 500 J / 10 s.
3. = 50 W. | thermodynamics |
Curved glass focuses rays to images, magnifying or projecting at will. | null | phy_0130 | concept | en | What are lenses for? | [
"Curved glass focuses rays to images, magnifying or projecting at will.",
"So the answer stands: Curved glass focuses rays to images, magnifying or projecting at will."
] | physics | Answer: Curved glass focuses rays to images, magnifying or projecting at will.
Steps:
1. Curved glass focuses rays to images, magnifying or projecting at will.
2. So the answer stands: Curved glass focuses rays to images, magnifying or projecting at will. | optics |
3rd harmonic: 360 Hz. | null | phy_0131 | worked_example | en | A string's fundamental is 120 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 120 Hz.",
"= 360 Hz."
] | physics | Answer: 3rd harmonic: 360 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 120 Hz.
3. = 360 Hz. | waves |
Mass crushed inside its horizon traps even light forever. | null | phy_0132 | concept | en | What is a black hole? | [
"Mass crushed inside its horizon traps even light forever.",
"So the answer stands: Mass crushed inside its horizon traps even light forever."
] | physics | Answer: Mass crushed inside its horizon traps even light forever.
Steps:
1. Mass crushed inside its horizon traps even light forever.
2. So the answer stands: Mass crushed inside its horizon traps even light forever. | modern |
Net force: 10 N. | null | phy_0133 | worked_example | en | A mass of 5 kg accelerates at 2 m/s². Compute the net force. | [
"F = m×a.",
"F = 5 kg × 2 m/s².",
"= 10 N."
] | physics | Answer: Net force: 10 N.
Steps:
1. F = m×a.
2. F = 5 kg × 2 m/s².
3. = 10 N. | mechanics |
Energie: 500 J. | null | phy_0134 | worked_example | cs | Topidlo 100 W běží po 5 s. Spočítej spotřebovanou energii. | [
"E = P×t.",
"E = 100 W × 5 s.",
"= 500 J."
] | physics | Answer: Energie: 500 J.
Steps:
1. E = P×t.
2. E = 100 W × 5 s.
3. = 500 J. | electromagnetism |
Heat: 25116 J. | null | phy_0135 | worked_example | en | How much heat warms 2 kg of water by 3 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 3 K.",
"= 25116 J."
] | physics | Answer: Heat: 25116 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 3 K.
2. = 25116 J. | thermodynamics |
Zdánlivá hloubka: 30 cm. | null | phy_0136 | worked_example | cs | Předmět leží 45 cm hluboko ve skle (n = 1,5). Spočítej zdánlivou hloubku. | [
"d' = d/n.",
"d' = 45 cm / 1,5.",
"= 30 cm."
] | physics | Answer: Zdánlivá hloubka: 30 cm.
Steps:
1. d' = d/n.
2. d' = 45 cm / 1,5.
3. = 30 cm. | optics |
The answer is Harmonics. | {
"A": "Harmonics",
"B": "Statics",
"C": "Noises",
"D": "Silences"
} | phy_0137 | multiple_choice | en | Choose: what colours timbre? | [
"Overtones added.",
"So: Harmonics.",
"Select option A."
] | physics | Answer: Harmonics
Steps:
1. Overtones added.
2. So: Harmonics.
3. Select option A.
Answer: (A) | waves |
Survivors: 600. | null | phy_0138 | worked_example | en | A sample of 2400 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 2400 → 1200.",
"Halve: 1200 → 600.",
"= 600."
] | physics | Answer: Survivors: 600.
Steps:
1. Halve: 2400 → 1200.
2. Halve: 1200 → 600.
3. = 600. | modern |
Work: 80 J. | null | phy_0139 | worked_example | en | A force of 20 N pushes 4 m. Compute the work done. | [
"W = F×d.",
"W = 20 N × 4 m.",
"= 80 J."
] | physics | Answer: Work: 80 J.
Steps:
1. W = F×d.
2. W = 20 N × 4 m.
3. = 80 J. | mechanics |
Voltage: 48 V. | null | phy_0140 | worked_example | en | A current of 4 A flows through 12 Ω. Compute the voltage. | [
"V = I×R.",
"V = 4 A × 12 Ω.",
"= 48 V."
] | physics | Answer: Voltage: 48 V.
Steps:
1. V = I×R.
2. V = 4 A × 12 Ω.
3. = 48 V. | electromagnetism |
Power: 70 W. | null | phy_0141 | worked_example | en | An engine does 700 J of work in 10 s. Compute its power. | [
"P = W/t.",
"P = 700 J / 10 s.",
"= 70 W."
] | physics | Answer: Power: 70 W.
Steps:
1. P = W/t.
2. P = 700 J / 10 s.
3. = 70 W. | thermodynamics |
Zvětšení je 2×. | {
"A": "2×",
"B": "1×",
"C": "3×",
"D": "4×"
} | phy_0142 | multiple_choice | cs | Obraz vzniká 20 cm od čočky, předmět v 10 cm. Jaké je zvětšení? | [
"M = 20 cm / 10 cm.",
"M = 2×.",
"Vyber možnost A."
] | physics | Answer: 2×
Steps:
1. M = 20 cm / 10 cm.
2. M = 2×.
3. Vyber možnost A.
Answer: (A) | optics |
Speed is 300 m/s. | {
"A": "250 m/s",
"B": "300 m/s",
"C": "350 m/s",
"D": "400 m/s"
} | phy_0143 | multiple_choice | en | A string wave has f = 150 Hz and λ = 2 m. What is its speed? | [
"v = 150 Hz × 2 m.",
"v = 300 m/s.",
"Select option B."
] | physics | Answer: 300 m/s
Steps:
1. v = 150 Hz × 2 m.
2. v = 300 m/s.
3. Select option B.
Answer: (B) | waves |
Quantum pairs at horizons leak energy, slowly evaporating holes. | null | phy_0144 | concept | en | Why Hawking radiation? | [
"Quantum pairs at horizons leak energy, slowly evaporating holes.",
"So the answer stands: Quantum pairs at horizons leak energy, slowly evaporating holes."
] | physics | Answer: Quantum pairs at horizons leak energy, slowly evaporating holes.
Steps:
1. Quantum pairs at horizons leak energy, slowly evaporating holes.
2. So the answer stands: Quantum pairs at horizons leak energy, slowly evaporating holes. | modern |
Kinetic energy is 25 J. | {
"A": "20 J",
"B": "30 J",
"C": "35 J",
"D": "25 J"
} | phy_0145 | multiple_choice | en | A 2 kg ball moves at 5 m/s. What is its kinetic energy? | [
"KE = ½×2 kg×(5 m/s)².",
"KE = 25 J.",
"Select option D."
] | physics | Answer: 25 J
Steps:
1. KE = ½×2 kg×(5 m/s)².
2. KE = 25 J.
3. Select option D.
Answer: (D) | mechanics |
Current is charge flow per second in amperes, the bloodstream of circuits. | null | phy_0146 | concept | en | What is current? | [
"Current is charge flow per second in amperes, the bloodstream of circuits.",
"So the answer stands: Current is charge flow per second in amperes, the bloodstream of circuits."
] | physics | Answer: Current is charge flow per second in amperes, the bloodstream of circuits.
Steps:
1. Current is charge flow per second in amperes, the bloodstream of circuits.
2. So the answer stands: Current is charge flow per second in amperes, the bloodstream of circuits. | electromagnetism |
The answer is Entropy. | {
"A": "Entropy",
"B": "Energy",
"C": "Mass",
"D": "Charge"
} | phy_0147 | multiple_choice | en | Choose: what never falls isolated? | [
"Second law rules.",
"So: Entropy.",
"Select option A."
] | physics | Answer: Entropy
Steps:
1. Second law rules.
2. So: Entropy.
3. Select option A.
Answer: (A) | thermodynamics |
Apparent depth: 40 cm. | null | phy_0148 | worked_example | en | An object sits 60 cm deep in glass (n = 1.5). Compute the apparent depth. | [
"d' = d/n.",
"d' = 60 cm / 1.5.",
"= 40 cm."
] | physics | Answer: Apparent depth: 40 cm.
Steps:
1. d' = d/n.
2. d' = 60 cm / 1.5.
3. = 40 cm. | optics |
Speed: 1050 m/s. | null | phy_0149 | worked_example | en | A string wave has f = 350 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 350 Hz × 3 m.",
"= 1050 m/s."
] | physics | Answer: Speed: 1050 m/s.
Steps:
1. v = f×λ.
2. v = 350 Hz × 3 m.
3. = 1050 m/s. | waves |
Lines: 15. | null | phy_0150 | worked_example | en | An atom is excited to level n = 6. Count the spectral lines it can emit. | [
"Pairs: 6×5/2.",
"= 30/2.",
"= 15."
] | physics | Answer: Lines: 15.
Steps:
1. Pairs: 6×5/2.
2. = 30/2.
3. = 15. | modern |
Setrvačnost je odpor hmotnosti vůči změně rychlosti. | null | phy_0151 | concept | cs | Co je setrvačnost? | [
"Setrvačnost je odpor hmotnosti vůči změně rychlosti.",
"Odpověď tedy platí: Setrvačnost je odpor hmotnosti vůči změně rychlosti."
] | physics | Answer: Setrvačnost je odpor hmotnosti vůči změně rychlosti.
Steps:
1. Setrvačnost je odpor hmotnosti vůči změně rychlosti.
2. Odpověď tedy platí: Setrvačnost je odpor hmotnosti vůči změně rychlosti. | mechanics |
Energy: 800 J. | null | phy_0152 | worked_example | en | A 100 W heater runs for 8 s. Compute the energy used. | [
"E = P×t.",
"E = 100 W × 8 s.",
"= 800 J."
] | physics | Answer: Energy: 800 J.
Steps:
1. E = P×t.
2. E = 100 W × 8 s.
3. = 800 J. | electromagnetism |
All objects emit photons by temperature, warming across empty space. | null | phy_0153 | concept | en | Why radiation? | [
"All objects emit photons by temperature, warming across empty space.",
"So the answer stands: All objects emit photons by temperature, warming across empty space."
] | physics | Answer: All objects emit photons by temperature, warming across empty space.
Steps:
1. All objects emit photons by temperature, warming across empty space.
2. So the answer stands: All objects emit photons by temperature, warming across empty space. | thermodynamics |
It marks where parallel rays meet, setting lens power in diopters. | null | phy_0154 | concept | en | Why focal length? | [
"It marks where parallel rays meet, setting lens power in diopters.",
"So the answer stands: It marks where parallel rays meet, setting lens power in diopters."
] | physics | Answer: It marks where parallel rays meet, setting lens power in diopters.
Steps:
1. It marks where parallel rays meet, setting lens power in diopters.
2. So the answer stands: It marks where parallel rays meet, setting lens power in diopters. | optics |
Cycles per second in hertz, setting pitch and colour. | null | phy_0155 | concept | en | What is frequency? | [
"Cycles per second in hertz, setting pitch and colour.",
"So the answer stands: Cycles per second in hertz, setting pitch and colour."
] | physics | Answer: Cycles per second in hertz, setting pitch and colour.
Steps:
1. Cycles per second in hertz, setting pitch and colour.
2. So the answer stands: Cycles per second in hertz, setting pitch and colour. | waves |
Pohybující se hodiny tikají pomaleji. | null | phy_0156 | concept | cs | Proč dilatace času? | [
"Pohybující se hodiny tikají pomaleji.",
"Odpověď tedy platí: Pohybující se hodiny tikají pomaleji."
] | physics | Answer: Pohybující se hodiny tikají pomaleji.
Steps:
1. Pohybující se hodiny tikají pomaleji.
2. Odpověď tedy platí: Pohybující se hodiny tikají pomaleji. | modern |
Momentum: 21 kg·m/s. | null | phy_0157 | worked_example | en | A mass of 7 kg moves at 3 m/s. Compute its momentum. | [
"p = m×v.",
"p = 7 kg × 3 m/s.",
"= 21 kg·m/s."
] | physics | Answer: Momentum: 21 kg·m/s.
Steps:
1. p = m×v.
2. p = 7 kg × 3 m/s.
3. = 21 kg·m/s. | mechanics |
Power: 75 W. | null | phy_0158 | worked_example | en | A current of 5 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (5 A)² × 3 Ω.",
"= 75 W."
] | physics | Answer: Power: 75 W.
Steps:
1. P = I²×R.
2. P = (5 A)² × 3 Ω.
3. = 75 W. | electromagnetism |
Temperature: 291 K. | null | phy_0159 | worked_example | en | Temperature is 18 °C. Convert it to kelvin. | [
"Add 273.",
"18 + 273.",
"= 291 K."
] | physics | Answer: Temperature: 291 K.
Steps:
1. Add 273.
2. 18 + 273.
3. = 291 K. | thermodynamics |
Čas je 1 s. | {
"A": "2 s",
"B": "1 s",
"C": "3 s",
"D": "0.5 s"
} | phy_0160 | multiple_choice | cs | Světlo letí 3×10⁸ m. Kolik sekund to trvá? (c = 3×10⁸ m/s) | [
"t = 3×10⁸ m / 3×10⁸ m/s.",
"t = 1 s.",
"Vyber možnost B."
] | physics | Answer: 1 s
Steps:
1. t = 3×10⁸ m / 3×10⁸ m/s.
2. t = 1 s.
3. Vyber možnost B.
Answer: (B) | optics |
Distance: 1700 m. | null | phy_0161 | worked_example | en | Thunder is heard 5 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 5 s.",
"= 1700 m."
] | physics | Answer: Distance: 1700 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 5 s.
3. = 1700 m. | waves |
Space expanded from a hot dense state 13.8 billion years ago. | null | phy_0162 | concept | en | What is the Big Bang? | [
"Space expanded from a hot dense state 13.8 billion years ago.",
"So the answer stands: Space expanded from a hot dense state 13.8 billion years ago."
] | physics | Answer: Space expanded from a hot dense state 13.8 billion years ago.
Steps:
1. Space expanded from a hot dense state 13.8 billion years ago.
2. So the answer stands: Space expanded from a hot dense state 13.8 billion years ago. | modern |
Kinetická energie je 16 J. | {
"A": "12 J",
"B": "20 J",
"C": "16 J",
"D": "24 J"
} | phy_0163 | multiple_choice | cs | Míč 2 kg letí 4 m/s. Jaká je jeho kinetická energie? | [
"KE = ½×2 kg×(4 m/s)².",
"KE = 16 J.",
"Vyber možnost C."
] | physics | Answer: 16 J
Steps:
1. KE = ½×2 kg×(4 m/s)².
2. KE = 16 J.
3. Vyber možnost C.
Answer: (C) | mechanics |
The answer is Changing flux. | {
"A": "Changing flux",
"B": "Steady heat",
"C": "Calm air",
"D": "Dark room"
} | phy_0164 | multiple_choice | en | Choose: what drives coils? | [
"Induction rules.",
"So: Changing flux.",
"Select option A."
] | physics | Answer: Changing flux
Steps:
1. Induction rules.
2. So: Changing flux.
3. Select option A.
Answer: (A) | electromagnetism |
Temperature is 294 K. | {
"A": "293 K",
"B": "294 K",
"C": "295 K",
"D": "296 K"
} | phy_0165 | multiple_choice | en | Room temperature is 21 °C. What is it in kelvin? | [
"21 °C + 273.",
"= 294 K.",
"Select option B."
] | physics | Answer: 294 K
Steps:
1. 21 °C + 273.
2. = 294 K.
3. Select option B.
Answer: (B) | thermodynamics |
Image size over object size, greater than one in microscopes. | null | phy_0166 | concept | en | What is magnification? | [
"Image size over object size, greater than one in microscopes.",
"So the answer stands: Image size over object size, greater than one in microscopes."
] | physics | Answer: Image size over object size, greater than one in microscopes.
Steps:
1. Image size over object size, greater than one in microscopes.
2. So the answer stands: Image size over object size, greater than one in microscopes. | optics |
Period is 0.33 s. | {
"A": "0.25 s",
"B": "0.2 s",
"C": "0.33 s",
"D": "0.5 s"
} | phy_0167 | multiple_choice | en | A wave has frequency 3 Hz. What is its period? | [
"T = 1 / 3 Hz.",
"T = 0.33 s.",
"Select option C."
] | physics | Answer: 0.33 s
Steps:
1. T = 1 / 3 Hz.
2. T = 0.33 s.
3. Select option C.
Answer: (C) | waves |
Nukleonové číslo: 7. | null | phy_0168 | worked_example | cs | Jádro má 3 protonů a 4 neutronů. Spočítej jeho nukleonové číslo. | [
"A = Z+N.",
"A = 3 + 4.",
"= 7."
] | physics | Answer: Nukleonové číslo: 7.
Steps:
1. A = Z+N.
2. A = 3 + 4.
3. = 7. | modern |
Hybnost: 15 kg·m/s. | null | phy_0169 | worked_example | cs | Těleso 5 kg se pohybuje 3 m/s. Spočítej jeho hybnost. | [
"p = m×v.",
"p = 5 kg × 3 m/s.",
"= 15 kg·m/s."
] | physics | Answer: Hybnost: 15 kg·m/s.
Steps:
1. p = m×v.
2. p = 5 kg × 3 m/s.
3. = 15 kg·m/s. | mechanics |
Voltage is 15 V. | {
"A": "10 V",
"B": "15 V",
"C": "20 V",
"D": "25 V"
} | phy_0170 | multiple_choice | en | A current of 3 A flows through 5 Ω. What is the voltage? | [
"V = 3 A × 5 Ω.",
"V = 15 V.",
"Select option B."
] | physics | Answer: 15 V
Steps:
1. V = 3 A × 5 Ω.
2. V = 15 V.
3. Select option B.
Answer: (B) | electromagnetism |
Energy conservation for heat and work: added heat splits into work and internal gain. | null | phy_0171 | concept | en | What is the first law? | [
"Energy conservation for heat and work: added heat splits into work and internal gain.",
"So the answer stands: Energy conservation for heat and work: added heat splits into work and internal gain."
] | physics | Answer: Energy conservation for heat and work: added heat splits into work and internal gain.
Steps:
1. Energy conservation for heat and work: added heat splits into work and internal gain.
2. So the answer stands: Energy conservation for heat and work: added heat splits into work and internal gain. | thermodynamics |
Magnification: 5×. | null | phy_0172 | worked_example | en | An image forms 50 cm from a lens, object at 10 cm. Compute the magnification. | [
"M = di/do.",
"M = 50 cm / 10 cm.",
"= 5×."
] | physics | Answer: Magnification: 5×.
Steps:
1. M = di/do.
2. M = 50 cm / 10 cm.
3. = 5×. | optics |
Vzdálenost: 1020 m. | null | phy_0173 | worked_example | cs | Hrom je slyšet 3 s po blesku. Jak daleko je bouře? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 3 s.",
"= 1020 m."
] | physics | Answer: Vzdálenost: 1020 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 3 s.
3. = 1020 m. | waves |
Distant galaxies recede faster with distance, stretching light red. | null | phy_0174 | concept | en | Why cosmic expansion? | [
"Distant galaxies recede faster with distance, stretching light red.",
"So the answer stands: Distant galaxies recede faster with distance, stretching light red."
] | physics | Answer: Distant galaxies recede faster with distance, stretching light red.
Steps:
1. Distant galaxies recede faster with distance, stretching light red.
2. So the answer stands: Distant galaxies recede faster with distance, stretching light red. | modern |
Každá síla má stejně velkého opačného partnera. | null | phy_0175 | concept | cs | Proč akce-reakce? | [
"Každá síla má stejně velkého opačného partnera.",
"Odpověď tedy platí: Každá síla má stejně velkého opačného partnera."
] | physics | Answer: Každá síla má stejně velkého opačného partnera.
Steps:
1. Každá síla má stejně velkého opačného partnera.
2. Odpověď tedy platí: Každá síla má stejně velkého opačného partnera. | mechanics |
Collisions inside conductors oppose drift, turning electric energy into heat. | null | phy_0176 | concept | en | Why resistance? | [
"Collisions inside conductors oppose drift, turning electric energy into heat.",
"So the answer stands: Collisions inside conductors oppose drift, turning electric energy into heat."
] | physics | Answer: Collisions inside conductors oppose drift, turning electric energy into heat.
Steps:
1. Collisions inside conductors oppose drift, turning electric energy into heat.
2. So the answer stands: Collisions inside conductors oppose drift, turning electric energy into heat. | electromagnetism |
It sums microscopic kinetic and potential stores, the hidden ledger of heat. | null | phy_0177 | concept | en | Why internal energy? | [
"It sums microscopic kinetic and potential stores, the hidden ledger of heat.",
"So the answer stands: It sums microscopic kinetic and potential stores, the hidden ledger of heat."
] | physics | Answer: It sums microscopic kinetic and potential stores, the hidden ledger of heat.
Steps:
1. It sums microscopic kinetic and potential stores, the hidden ledger of heat.
2. So the answer stands: It sums microscopic kinetic and potential stores, the hidden ledger of heat. | thermodynamics |
1/f equals 1/do + 1/di, locating every image from object spots. | null | phy_0178 | concept | en | Why lens equation? | [
"1/f equals 1/do + 1/di, locating every image from object spots.",
"So the answer stands: 1/f equals 1/do + 1/di, locating every image from object spots."
] | physics | Answer: 1/f equals 1/do + 1/di, locating every image from object spots.
Steps:
1. 1/f equals 1/do + 1/di, locating every image from object spots.
2. So the answer stands: 1/f equals 1/do + 1/di, locating every image from object spots. | optics |
3rd harmonic: 390 Hz. | null | phy_0179 | worked_example | en | A string's fundamental is 130 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 130 Hz.",
"= 390 Hz."
] | physics | Answer: 3rd harmonic: 390 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 130 Hz.
3. = 390 Hz. | waves |
Přeživší: 400. | null | phy_0180 | worked_example | cs | Vzorek 1600 atomů projde 2 poločasy. Spočítej přeživší. | [
"Půl: 1600 → 800.",
"Půl: 800 → 400.",
"= 400."
] | physics | Answer: Přeživší: 400.
Steps:
1. Půl: 1600 → 800.
2. Půl: 800 → 400.
3. = 400. | modern |
Net force: 12 N. | null | phy_0181 | worked_example | en | A mass of 6 kg accelerates at 2 m/s². Compute the net force. | [
"F = m×a.",
"F = 6 kg × 2 m/s².",
"= 12 N."
] | physics | Answer: Net force: 12 N.
Steps:
1. F = m×a.
2. F = 6 kg × 2 m/s².
3. = 12 N. | mechanics |
Power is 48 W. | {
"A": "36 W",
"B": "60 W",
"C": "48 W",
"D": "72 W"
} | phy_0182 | multiple_choice | en | A bulb runs at 12 V drawing 4 A. What is its power? | [
"P = 12 V × 4 A.",
"P = 48 W.",
"Select option C."
] | physics | Answer: 48 W
Steps:
1. P = 12 V × 4 A.
2. P = 48 W.
3. Select option C.
Answer: (C) | electromagnetism |
Heat needed is 12558 J. | {
"A": "8372 J",
"B": "16744 J",
"C": "12558 J",
"D": "20930 J"
} | phy_0183 | multiple_choice | en | How much heat warms 1 kg of water by 3 K? (c = 4186 J/(kg·K)) | [
"Q = 1 kg × 4186 J/(kg·K) × 3 K.",
"Q = 12558 J.",
"Select option C."
] | physics | Answer: 12558 J
Steps:
1. Q = 1 kg × 4186 J/(kg·K) × 3 K.
2. Q = 12558 J.
3. Select option C.
Answer: (C) | thermodynamics |
Time: 3.3 s. | null | phy_0184 | worked_example | en | Light travels 10×10⁸ m. Compute the travel time. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 10×10⁸ / 3×10⁸ s.",
"= 3.3 s."
] | physics | Answer: Time: 3.3 s.
Steps:
1. t = d/c.
2. t = 10×10⁸ / 3×10⁸ s.
3. = 3.3 s. | optics |
Speed: 1200 m/s. | null | phy_0185 | worked_example | en | A string wave has f = 400 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 400 Hz × 3 m.",
"= 1200 m/s."
] | physics | Answer: Speed: 1200 m/s.
Steps:
1. v = f×λ.
2. v = 400 Hz × 3 m.
3. = 1200 m/s. | waves |
Mass number: 11. | null | phy_0186 | worked_example | en | A nucleus has 5 protons and 6 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 5 + 6.",
"= 11."
] | physics | Answer: Mass number: 11.
Steps:
1. A = Z+N.
2. A = 5 + 6.
3. = 11. | modern |
Every force has an equal opposite partner on the other body, conserving momentum always. | null | phy_0187 | concept | en | Why action-reaction? | [
"Every force has an equal opposite partner on the other body, conserving momentum always.",
"So the answer stands: Every force has an equal opposite partner on the other body, conserving momentum always."
] | physics | Answer: Every force has an equal opposite partner on the other body, conserving momentum always.
Steps:
1. Every force has an equal opposite partner on the other body, conserving momentum always.
2. So the answer stands: Every force has an equal opposite partner on the other body, conserving momentum always. | mechanics |
Voltage: 60 V. | null | phy_0188 | worked_example | en | A current of 5 A flows through 12 Ω. Compute the voltage. | [
"V = I×R.",
"V = 5 A × 12 Ω.",
"= 60 V."
] | physics | Answer: Voltage: 60 V.
Steps:
1. V = I×R.
2. V = 5 A × 12 Ω.
3. = 60 V. | electromagnetism |
Heat: 33488 J. | null | phy_0189 | worked_example | en | How much heat warms 2 kg of water by 4 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 4 K.",
"= 33488 J."
] | physics | Answer: Heat: 33488 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 4 K.
2. = 33488 J. | thermodynamics |
Rays truly meet there, so screens catch it, unlike virtual mirages. | null | phy_0190 | concept | en | What is a real image? | [
"Rays truly meet there, so screens catch it, unlike virtual mirages.",
"So the answer stands: Rays truly meet there, so screens catch it, unlike virtual mirages."
] | physics | Answer: Rays truly meet there, so screens catch it, unlike virtual mirages.
Steps:
1. Rays truly meet there, so screens catch it, unlike virtual mirages.
2. So the answer stands: Rays truly meet there, so screens catch it, unlike virtual mirages. | optics |
Speed equals cycles times length, the master wave relation. | null | phy_0191 | concept | en | Why v equals fλ? | [
"Speed equals cycles times length, the master wave relation.",
"So the answer stands: Speed equals cycles times length, the master wave relation."
] | physics | Answer: Speed equals cycles times length, the master wave relation.
Steps:
1. Speed equals cycles times length, the master wave relation.
2. So the answer stands: Speed equals cycles times length, the master wave relation. | waves |
Survivors: 800. | null | phy_0192 | worked_example | en | A sample of 3200 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 3200 → 1600.",
"Halve: 1600 → 800.",
"= 800."
] | physics | Answer: Survivors: 800.
Steps:
1. Halve: 3200 → 1600.
2. Halve: 1600 → 800.
3. = 800. | modern |
The answer is F equals ma. | {
"A": "F equals ma",
"B": "E equals mc",
"C": "V equals IR",
"D": "pV equals nRT"
} | phy_0193 | multiple_choice | en | Choose: what links push, motion? | [
"Second law binds.",
"So: F equals ma.",
"Select option A."
] | physics | Answer: F equals ma
Steps:
1. Second law binds.
2. So: F equals ma.
3. Select option A.
Answer: (A) | mechanics |
Energy: 900 J. | null | phy_0194 | worked_example | en | A 100 W heater runs for 9 s. Compute the energy used. | [
"E = P×t.",
"E = 100 W × 9 s.",
"= 900 J."
] | physics | Answer: Energy: 900 J.
Steps:
1. E = P×t.
2. E = 100 W × 9 s.
3. = 900 J. | electromagnetism |
Power: 80 W. | null | phy_0195 | worked_example | en | An engine does 800 J of work in 10 s. Compute its power. | [
"P = W/t.",
"P = 800 J / 10 s.",
"= 80 W."
] | physics | Answer: Power: 80 W.
Steps:
1. P = W/t.
2. P = 800 J / 10 s.
3. = 80 W. | thermodynamics |
The answer is Refraction. | {
"A": "Refraction",
"B": "Reflection",
"C": "Ejection",
"D": "Injection"
} | phy_0196 | multiple_choice | en | Choose: what bends at boundaries? | [
"Speeds differ.",
"So: Refraction.",
"Select option A."
] | physics | Answer: Refraction
Steps:
1. Speeds differ.
2. So: Refraction.
3. Select option A.
Answer: (A) | optics |
Perioda je 0,5 s. | {
"A": "0,33 s",
"B": "0,5 s",
"C": "0,25 s",
"D": "1 s"
} | phy_0197 | multiple_choice | cs | Vlna má frekvenci 2 Hz. Jaká je její perioda? | [
"T = 1 / 2 Hz.",
"T = 0,5 s.",
"Vyber možnost B."
] | physics | Answer: 0,5 s
Steps:
1. T = 1 / 2 Hz.
2. T = 0,5 s.
3. Vyber možnost B.
Answer: (B) | waves |
Čar: 10. | null | phy_0198 | worked_example | cs | Atom je vybuzen do hladiny n = 5. Spočítej čáry, jež může vyzářit. | [
"Dvojice: 5×4/2.",
"= 20/2.",
"= 10."
] | physics | Answer: Čar: 10.
Steps:
1. Dvojice: 5×4/2.
2. = 20/2.
3. = 10. | modern |
Tření brání klouzání a mění pohyb v teplo. | null | phy_0199 | concept | cs | Co je tření? | [
"Tření brání klouzání a mění pohyb v teplo.",
"Odpověď tedy platí: Tření brání klouzání a mění pohyb v teplo."
] | physics | Answer: Tření brání klouzání a mění pohyb v teplo.
Steps:
1. Tření brání klouzání a mění pohyb v teplo.
2. Odpověď tedy platí: Tření brání klouzání a mění pohyb v teplo. | mechanics |
Power VI in watts rates energy delivery, sizing bulbs and bills. | null | phy_0200 | concept | en | What is electric power? | [
"Power VI in watts rates energy delivery, sizing bulbs and bills.",
"So the answer stands: Power VI in watts rates energy delivery, sizing bulbs and bills."
] | physics | Answer: Power VI in watts rates energy delivery, sizing bulbs and bills.
Steps:
1. Power VI in watts rates energy delivery, sizing bulbs and bills.
2. So the answer stands: Power VI in watts rates energy delivery, sizing bulbs and bills. | electromagnetism |
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