answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
Odpověď je dostředivá síla. | {
"A": "dostředivá síla",
"B": "tření",
"C": "tíha",
"D": "vztlak"
} | phy_0601 | multiple_choice | cs | Vyber: co ohýbá kruhy? | [
"Dovnitř táhne.",
"Tedy: dostředivá síla.",
"Vyber možnost A."
] | physics | Answer: dostředivá síla
Steps:
1. Dovnitř táhne.
2. Tedy: dostředivá síla.
3. Vyber možnost A.
Answer: (A) | mechanics |
Ground wires sink fault currents safely, protecting people from shocks. | null | phy_0602 | concept | en | Why grounding? | [
"Ground wires sink fault currents safely, protecting people from shocks.",
"So the answer stands: Ground wires sink fault currents safely, protecting people from shocks."
] | physics | Answer: Ground wires sink fault currents safely, protecting people from shocks.
Steps:
1. Ground wires sink fault currents safely, protecting people from shocks.
2. So the answer stands: Ground wires sink fault currents safely, protecting people from shocks. | electromagnetism |
Condensing steam dumps huge latent heat onto skin rapidly. | null | phy_0603 | concept | en | Why steam burns? | [
"Condensing steam dumps huge latent heat onto skin rapidly.",
"So the answer stands: Condensing steam dumps huge latent heat onto skin rapidly."
] | physics | Answer: Condensing steam dumps huge latent heat onto skin rapidly.
Steps:
1. Condensing steam dumps huge latent heat onto skin rapidly.
2. So the answer stands: Condensing steam dumps huge latent heat onto skin rapidly. | thermodynamics |
Apparent depth: 120 cm. | null | phy_0604 | worked_example | en | An object sits 180 cm deep in glass (n = 1.5). Compute the apparent depth. | [
"d' = d/n.",
"d' = 180 cm / 1.5.",
"= 120 cm."
] | physics | Answer: Apparent depth: 120 cm.
Steps:
1. d' = d/n.
2. d' = 180 cm / 1.5.
3. = 120 cm. | optics |
Centimetre waves heat food by shaking water molecules. | null | phy_0605 | concept | en | What are microwaves? | [
"Centimetre waves heat food by shaking water molecules.",
"So the answer stands: Centimetre waves heat food by shaking water molecules."
] | physics | Answer: Centimetre waves heat food by shaking water molecules.
Steps:
1. Centimetre waves heat food by shaking water molecules.
2. So the answer stands: Centimetre waves heat food by shaking water molecules. | waves |
Mass number is 12. | {
"A": "11",
"B": "13",
"C": "12",
"D": "14"
} | phy_0606 | multiple_choice | en | A nucleus has 6 protons and 6 neutrons. What is its mass number? | [
"A = 6 + 6.",
"A = 12.",
"Select option C."
] | physics | Answer: 12
Steps:
1. A = 6 + 6.
2. A = 12.
3. Select option C.
Answer: (C) | modern |
Zero net force and torque keep structures still, the rule behind bridges. | null | phy_0607 | concept | en | Why static equilibrium? | [
"Zero net force and torque keep structures still, the rule behind bridges.",
"So the answer stands: Zero net force and torque keep structures still, the rule behind bridges."
] | physics | Answer: Zero net force and torque keep structures still, the rule behind bridges.
Steps:
1. Zero net force and torque keep structures still, the rule behind bridges.
2. So the answer stands: Zero net force and torque keep structures still, the rule behind bridges. | mechanics |
Power: 432 W. | null | phy_0608 | worked_example | en | A current of 12 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (12 A)² × 3 Ω.",
"= 432 W."
] | physics | Answer: Power: 432 W.
Steps:
1. P = I²×R.
2. P = (12 A)² × 3 Ω.
3. = 432 W. | electromagnetism |
Temperature: 300 K. | null | phy_0609 | worked_example | en | Temperature is 27 °C. Convert it to kelvin. | [
"Add 273.",
"27 + 273.",
"= 300 K."
] | physics | Answer: Temperature: 300 K.
Steps:
1. Add 273.
2. 27 + 273.
3. = 300 K. | thermodynamics |
Zakřivené sklo soustřeďuje paprsky do obrazů. | null | phy_0610 | concept | cs | K čemu čočky? | [
"Zakřivené sklo soustřeďuje paprsky do obrazů.",
"Odpověď tedy platí: Zakřivené sklo soustřeďuje paprsky do obrazů."
] | physics | Answer: Zakřivené sklo soustřeďuje paprsky do obrazů.
Steps:
1. Zakřivené sklo soustřeďuje paprsky do obrazů.
2. Odpověď tedy platí: Zakřivené sklo soustřeďuje paprsky do obrazů. | optics |
3rd harmonic is 450 Hz. | {
"A": "420 Hz",
"B": "480 Hz",
"C": "450 Hz",
"D": "510 Hz"
} | phy_0611 | multiple_choice | en | A string's fundamental is 150 Hz. What is its 3rd harmonic? | [
"f3 = 3 × 150 Hz.",
"f3 = 450 Hz.",
"Select option C."
] | physics | Answer: 450 Hz
Steps:
1. f3 = 3 × 150 Hz.
2. f3 = 450 Hz.
3. Select option C.
Answer: (C) | waves |
Mass number: 29. | null | phy_0612 | worked_example | en | A nucleus has 14 protons and 15 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 14 + 15.",
"= 29."
] | physics | Answer: Mass number: 29.
Steps:
1. A = Z+N.
2. A = 14 + 15.
3. = 29. | modern |
Spring force equals −kx, pulling back proportionally to stretch distance. | null | phy_0613 | concept | en | What is Hooke's law? | [
"Spring force equals −kx, pulling back proportionally to stretch distance.",
"So the answer stands: Spring force equals −kx, pulling back proportionally to stretch distance."
] | physics | Answer: Spring force equals −kx, pulling back proportionally to stretch distance.
Steps:
1. Spring force equals −kx, pulling back proportionally to stretch distance.
2. So the answer stands: Spring force equals −kx, pulling back proportionally to stretch distance. | mechanics |
Voltage: 144 V. | null | phy_0614 | worked_example | en | A current of 12 A flows through 12 Ω. Compute the voltage. | [
"V = I×R.",
"V = 12 A × 12 Ω.",
"= 144 V."
] | physics | Answer: Voltage: 144 V.
Steps:
1. V = I×R.
2. V = 12 A × 12 Ω.
3. = 144 V. | electromagnetism |
Heat needed is 25116 J. | {
"A": "20930 J",
"B": "25116 J",
"C": "29302 J",
"D": "33488 J"
} | phy_0615 | multiple_choice | en | How much heat warms 1 kg of water by 6 K? (c = 4186 J/(kg·K)) | [
"Q = 1 kg × 4186 J/(kg·K) × 6 K.",
"Q = 25116 J.",
"Select option B."
] | physics | Answer: 25116 J
Steps:
1. Q = 1 kg × 4186 J/(kg·K) × 6 K.
2. Q = 25116 J.
3. Select option B.
Answer: (B) | thermodynamics |
Short-focus lenses magnify tiny things hugely in stages. | null | phy_0616 | concept | en | What is a microscope? | [
"Short-focus lenses magnify tiny things hugely in stages.",
"So the answer stands: Short-focus lenses magnify tiny things hugely in stages."
] | physics | Answer: Short-focus lenses magnify tiny things hugely in stages.
Steps:
1. Short-focus lenses magnify tiny things hugely in stages.
2. So the answer stands: Short-focus lenses magnify tiny things hugely in stages. | optics |
The answer is Standing waves. | {
"A": "Running rivers",
"B": "Falling rocks",
"C": "Flying birds",
"D": "Standing waves"
} | phy_0617 | multiple_choice | en | Choose: what locks into notes? | [
"Nodes fixed.",
"So: Standing waves.",
"Select option D."
] | physics | Answer: Standing waves
Steps:
1. Nodes fixed.
2. So: Standing waves.
3. Select option D.
Answer: (D) | waves |
Prostor se rozpínal z horkého hustého stavu. | null | phy_0618 | concept | cs | Proč velký třesk? | [
"Prostor se rozpínal z horkého hustého stavu.",
"Odpověď tedy platí: Prostor se rozpínal z horkého hustého stavu."
] | physics | Answer: Prostor se rozpínal z horkého hustého stavu.
Steps:
1. Prostor se rozpínal z horkého hustého stavu.
2. Odpověď tedy platí: Prostor se rozpínal z horkého hustého stavu. | modern |
Výsledná síla je 9 N. | {
"A": "6 N",
"B": "9 N",
"C": "12 N",
"D": "15 N"
} | phy_0619 | multiple_choice | cs | Těleso 3 kg zrychluje 3 m/s². Jaká je výsledná síla? | [
"F = 3 kg × 3 m/s².",
"F = 9 N.",
"Vyber možnost B."
] | physics | Answer: 9 N
Steps:
1. F = 3 kg × 3 m/s².
2. F = 9 N.
3. Vyber možnost B.
Answer: (B) | mechanics |
Energy: 1600 J. | null | phy_0620 | worked_example | en | A 100 W heater runs for 16 s. Compute the energy used. | [
"E = P×t.",
"E = 100 W × 16 s.",
"= 1600 J."
] | physics | Answer: Energy: 1600 J.
Steps:
1. E = P×t.
2. E = 100 W × 16 s.
3. = 1600 J. | electromagnetism |
Účinnost je 30 %. | {
"A": "20 %",
"B": "40 %",
"C": "50 %",
"D": "30 %"
} | phy_0621 | multiple_choice | cs | Motor mění 300 J z 1000 J tepla v práci. Jaká je jeho účinnost? | [
"300 J / 1000 J.",
"= 30 %.",
"Vyber možnost D."
] | physics | Answer: 30 %
Steps:
1. 300 J / 1000 J.
2. = 30 %.
3. Vyber možnost D.
Answer: (D) | thermodynamics |
Apparent depth is 70 cm. | {
"A": "65 cm",
"B": "75 cm",
"C": "80 cm",
"D": "70 cm"
} | phy_0622 | multiple_choice | en | An object sits 105 cm deep in glass (n = 1.5). What is the apparent depth? | [
"d' = 105 cm / 1.5.",
"d' = 70 cm.",
"Select option D."
] | physics | Answer: 70 cm
Steps:
1. d' = 105 cm / 1.5.
2. d' = 70 cm.
3. Select option D.
Answer: (D) | optics |
Short waves pierce flesh but stop at calcium. | null | phy_0623 | concept | en | Why X-rays see bones? | [
"Short waves pierce flesh but stop at calcium.",
"So the answer stands: Short waves pierce flesh but stop at calcium."
] | physics | Answer: Short waves pierce flesh but stop at calcium.
Steps:
1. Short waves pierce flesh but stop at calcium.
2. So the answer stands: Short waves pierce flesh but stop at calcium. | waves |
Zbude 200 atomů. | {
"A": "150",
"B": "200",
"C": "250",
"D": "300"
} | phy_0624 | multiple_choice | cs | Vzorek 800 atomů projde 2 poločasy. Kolik atomů zbude? | [
"Půlit dvakrát: 800 → 400 → 200.",
"Zbývá: 200.",
"Vyber možnost B."
] | physics | Answer: 200
Steps:
1. Půlit dvakrát: 800 → 400 → 200.
2. Zbývá: 200.
3. Vyber možnost B.
Answer: (B) | modern |
Výsledná síla: 12 N. | null | phy_0625 | worked_example | cs | Těleso 6 kg zrychluje 2 m/s². Spočítej výslednou sílu. | [
"F = m×a.",
"F = 6 kg × 2 m/s².",
"= 12 N."
] | physics | Answer: Výsledná síla: 12 N.
Steps:
1. F = m×a.
2. F = 6 kg × 2 m/s².
3. = 12 N. | mechanics |
Charge is 120 C. | {
"A": "100 C",
"B": "140 C",
"C": "120 C",
"D": "160 C"
} | phy_0626 | multiple_choice | en | A current of 4 A flows for 30 s. How much charge passes? | [
"Q = 4 A × 30 s.",
"Q = 120 C.",
"Select option C."
] | physics | Answer: 120 C
Steps:
1. Q = 4 A × 30 s.
2. Q = 120 C.
3. Select option C.
Answer: (C) | electromagnetism |
Efficiency is 60%. | {
"A": "50%",
"B": "70%",
"C": "60%",
"D": "80%"
} | phy_0627 | multiple_choice | en | An engine turns 600 J of 1000 J heat into work. What is its efficiency? | [
"600 J / 1000 J.",
"= 60%.",
"Select option C."
] | physics | Answer: 60%
Steps:
1. 600 J / 1000 J.
2. = 60%.
3. Select option C.
Answer: (C) | thermodynamics |
Magnification: 13×. | null | phy_0628 | worked_example | en | An image forms 130 cm from a lens, object at 10 cm. Compute the magnification. | [
"M = di/do.",
"M = 130 cm / 10 cm.",
"= 13×."
] | physics | Answer: Magnification: 13×.
Steps:
1. M = di/do.
2. M = 130 cm / 10 cm.
3. = 13×. | optics |
Distance: 4420 m. | null | phy_0629 | worked_example | en | Thunder is heard 13 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 13 s.",
"= 4420 m."
] | physics | Answer: Distance: 4420 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 13 s.
3. = 4420 m. | waves |
Quarks, leptons, and bosons explain all known particles and forces. | null | phy_0630 | concept | en | What is the Standard Model? | [
"Quarks, leptons, and bosons explain all known particles and forces.",
"So the answer stands: Quarks, leptons, and bosons explain all known particles and forces."
] | physics | Answer: Quarks, leptons, and bosons explain all known particles and forces.
Steps:
1. Quarks, leptons, and bosons explain all known particles and forces.
2. So the answer stands: Quarks, leptons, and bosons explain all known particles and forces. | modern |
Rychlost je 11 m/s. | {
"A": "10 m/s",
"B": "12 m/s",
"C": "11 m/s",
"D": "13 m/s"
} | phy_0631 | multiple_choice | cs | Auto ujede 110 m za 10 s. Jaká je jeho rychlost? | [
"v = 110 m / 10 s.",
"v = 11 m/s.",
"Vyber možnost C."
] | physics | Answer: 11 m/s
Steps:
1. v = 110 m / 10 s.
2. v = 11 m/s.
3. Vyber možnost C.
Answer: (C) | mechanics |
The answer is Magnetic field. | {
"A": "Gravity well",
"B": "Sound wave",
"C": "Heat haze",
"D": "Magnetic field"
} | phy_0632 | multiple_choice | en | Choose: what does motion create? | [
"Currents loop fields.",
"So: Magnetic field.",
"Select option D."
] | physics | Answer: Magnetic field
Steps:
1. Currents loop fields.
2. So: Magnetic field.
3. Select option D.
Answer: (D) | electromagnetism |
Equal temperatures stop net heat flow, defining temperature itself. | null | phy_0633 | concept | en | What is thermal equilibrium? | [
"Equal temperatures stop net heat flow, defining temperature itself.",
"So the answer stands: Equal temperatures stop net heat flow, defining temperature itself."
] | physics | Answer: Equal temperatures stop net heat flow, defining temperature itself.
Steps:
1. Equal temperatures stop net heat flow, defining temperature itself.
2. So the answer stands: Equal temperatures stop net heat flow, defining temperature itself. | thermodynamics |
Oil raises numerical aperture, resolving finer detail sharply. | null | phy_0634 | concept | en | Why oil immersion? | [
"Oil raises numerical aperture, resolving finer detail sharply.",
"So the answer stands: Oil raises numerical aperture, resolving finer detail sharply."
] | physics | Answer: Oil raises numerical aperture, resolving finer detail sharply.
Steps:
1. Oil raises numerical aperture, resolving finer detail sharply.
2. So the answer stands: Oil raises numerical aperture, resolving finer detail sharply. | optics |
Overlapping waves sum by phase, building holograms and noise control. | null | phy_0635 | concept | en | What is wave interference? | [
"Overlapping waves sum by phase, building holograms and noise control.",
"So the answer stands: Overlapping waves sum by phase, building holograms and noise control."
] | physics | Answer: Overlapping waves sum by phase, building holograms and noise control.
Steps:
1. Overlapping waves sum by phase, building holograms and noise control.
2. So the answer stands: Overlapping waves sum by phase, building holograms and noise control. | waves |
The answer is Half-life. | {
"A": "Full moon",
"B": "High tide",
"C": "Leap year",
"D": "Half-life"
} | phy_0636 | multiple_choice | en | Choose: what halves statistically? | [
"Rocks dated.",
"So: Half-life.",
"Select option D."
] | physics | Answer: Half-life
Steps:
1. Rocks dated.
2. So: Half-life.
3. Select option D.
Answer: (D) | modern |
Restoring force linear in displacement makes sinusoidal oscillation with fixed period. | null | phy_0637 | concept | en | Why simple harmonic motion? | [
"Restoring force linear in displacement makes sinusoidal oscillation with fixed period.",
"So the answer stands: Restoring force linear in displacement makes sinusoidal oscillation with fixed period."
] | physics | Answer: Restoring force linear in displacement makes sinusoidal oscillation with fixed period.
Steps:
1. Restoring force linear in displacement makes sinusoidal oscillation with fixed period.
2. So the answer stands: Restoring force linear in displacement makes sinusoidal oscillation with fixed period. | mechanics |
Power: 507 W. | null | phy_0638 | worked_example | en | A current of 13 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (13 A)² × 3 Ω.",
"= 507 W."
] | physics | Answer: Power: 507 W.
Steps:
1. P = I²×R.
2. P = (13 A)² × 3 Ω.
3. = 507 W. | electromagnetism |
The answer is Conduction. | {
"A": "Singing",
"B": "Dancing",
"C": "Sleeping",
"D": "Conduction"
} | phy_0639 | multiple_choice | en | Choose: what hands energy along? | [
"Collisions pass heat.",
"So: Conduction.",
"Select option D."
] | physics | Answer: Conduction
Steps:
1. Collisions pass heat.
2. So: Conduction.
3. Select option D.
Answer: (D) | thermodynamics |
Značí setkání rovnoběžných paprsků. | null | phy_0640 | concept | cs | Proč ohnisková vzdálenost? | [
"Značí setkání rovnoběžných paprsků.",
"Odpověď tedy platí: Značí setkání rovnoběžných paprsků."
] | physics | Answer: Značí setkání rovnoběžných paprsků.
Steps:
1. Značí setkání rovnoběžných paprsků.
2. Odpověď tedy platí: Značí setkání rovnoběžných paprsků. | optics |
Anti-phase sound erases rumble, silencing cabins and headphones. | null | phy_0641 | concept | en | Why noise cancelling? | [
"Anti-phase sound erases rumble, silencing cabins and headphones.",
"So the answer stands: Anti-phase sound erases rumble, silencing cabins and headphones."
] | physics | Answer: Anti-phase sound erases rumble, silencing cabins and headphones.
Steps:
1. Anti-phase sound erases rumble, silencing cabins and headphones.
2. So the answer stands: Anti-phase sound erases rumble, silencing cabins and headphones. | waves |
Survivors: 2600. | null | phy_0642 | worked_example | en | A sample of 10400 atoms undergoes 2 half-lives. Compute the survivors. | [
"Halve: 10400 → 5200.",
"Halve: 5200 → 2600.",
"= 2600."
] | physics | Answer: Survivors: 2600.
Steps:
1. Halve: 10400 → 5200.
2. Halve: 5200 → 2600.
3. = 2600. | modern |
Work: 240 J. | null | phy_0643 | worked_example | en | A force of 60 N pushes 4 m. Compute the work done. | [
"W = F×d.",
"W = 60 N × 4 m.",
"= 240 J."
] | physics | Answer: Work: 240 J.
Steps:
1. W = F×d.
2. W = 60 N × 4 m.
3. = 240 J. | mechanics |
The answer is Fuse. | {
"A": "Fuse",
"B": "Bulb",
"C": "Wire",
"D": "Plug"
} | phy_0644 | multiple_choice | en | Choose: what melts to save? | [
"Excess sacrificed.",
"So: Fuse.",
"Select option A."
] | physics | Answer: Fuse
Steps:
1. Excess sacrificed.
2. So: Fuse.
3. Select option A.
Answer: (A) | electromagnetism |
The answer is Blackbody glow. | {
"A": "Blackbody glow",
"B": "Neon sign",
"C": "Candle flame",
"D": "Laser dot"
} | phy_0645 | multiple_choice | en | Choose: what peaks by temperature? | [
"Quanta founded.",
"So: Blackbody glow.",
"Select option A."
] | physics | Answer: Blackbody glow
Steps:
1. Quanta founded.
2. So: Blackbody glow.
3. Select option A.
Answer: (A) | thermodynamics |
Diffraction limits smallest separable spots to wavelength over aperture. | null | phy_0646 | concept | en | What is resolution? | [
"Diffraction limits smallest separable spots to wavelength over aperture.",
"So the answer stands: Diffraction limits smallest separable spots to wavelength over aperture."
] | physics | Answer: Diffraction limits smallest separable spots to wavelength over aperture.
Steps:
1. Diffraction limits smallest separable spots to wavelength over aperture.
2. So the answer stands: Diffraction limits smallest separable spots to wavelength over aperture. | optics |
Vzdálenost: 1360 m. | null | phy_0647 | worked_example | cs | Hrom je slyšet 4 s po blesku. Jak daleko je bouře? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 4 s.",
"= 1360 m."
] | physics | Answer: Vzdálenost: 1360 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 4 s.
3. = 1360 m. | waves |
Počet: 6. | {
"A": "5",
"B": "7",
"C": "6",
"D": "8"
} | phy_0648 | multiple_choice | cs | Atom je vybuzen do hladiny n = 4. Kolik spektrálních čar může vyzářit? | [
"Dvojice: 4×3/2.",
"Čar: 6.",
"Vyber možnost C."
] | physics | Answer: 6
Steps:
1. Dvojice: 4×3/2.
2. Čar: 6.
3. Vyber možnost C.
Answer: (C) | modern |
Speed is 15 m/s. | {
"A": "14 m/s",
"B": "16 m/s",
"C": "15 m/s",
"D": "17 m/s"
} | phy_0649 | multiple_choice | en | A car travels 150 m in 10 s. What is its speed? | [
"v = 150 m / 10 s.",
"v = 15 m/s.",
"Select option C."
] | physics | Answer: 15 m/s
Steps:
1. v = 150 m / 10 s.
2. v = 15 m/s.
3. Select option C.
Answer: (C) | mechanics |
Fuses melt at excess current, sacrificing themselves to save circuits. | null | phy_0650 | concept | en | What is a fuse? | [
"Fuses melt at excess current, sacrificing themselves to save circuits.",
"So the answer stands: Fuses melt at excess current, sacrificing themselves to save circuits."
] | physics | Answer: Fuses melt at excess current, sacrificing themselves to save circuits.
Steps:
1. Fuses melt at excess current, sacrificing themselves to save circuits.
2. So the answer stands: Fuses melt at excess current, sacrificing themselves to save circuits. | electromagnetism |
Heat: 108836 J. | null | phy_0651 | worked_example | en | How much heat warms 2 kg of water by 13 K? (c = 4186 J/(kg·K)) | [
"Q = 2 kg × 4186 J/(kg·K) × 13 K.",
"= 108836 J."
] | physics | Answer: Heat: 108836 J.
Steps:
1. Q = 2 kg × 4186 J/(kg·K) × 13 K.
2. = 108836 J. | thermodynamics |
Time: 11.3 s. | null | phy_0652 | worked_example | en | Light travels 34×10⁸ m. Compute the travel time. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 34×10⁸ / 3×10⁸ s.",
"= 11.3 s."
] | physics | Answer: Time: 11.3 s.
Steps:
1. t = d/c.
2. t = 34×10⁸ / 3×10⁸ s.
3. = 11.3 s. | optics |
Pohyb posouvá slyšenou frekvenci. | null | phy_0653 | concept | cs | Proč Dopplerův jev? | [
"Pohyb posouvá slyšenou frekvenci.",
"Odpověď tedy platí: Pohyb posouvá slyšenou frekvenci."
] | physics | Answer: Pohyb posouvá slyšenou frekvenci.
Steps:
1. Pohyb posouvá slyšenou frekvenci.
2. Odpověď tedy platí: Pohyb posouvá slyšenou frekvenci. | waves |
Čar: 15. | null | phy_0654 | worked_example | cs | Atom je vybuzen do hladiny n = 6. Spočítej čáry, jež může vyzářit. | [
"Dvojice: 6×5/2.",
"= 30/2.",
"= 15."
] | physics | Answer: Čar: 15.
Steps:
1. Dvojice: 6×5/2.
2. = 30/2.
3. = 15. | modern |
Kinetic energy is 81 J. | {
"A": "72 J",
"B": "90 J",
"C": "99 J",
"D": "81 J"
} | phy_0655 | multiple_choice | en | A 2 kg ball moves at 9 m/s. What is its kinetic energy? | [
"KE = ½×2 kg×(9 m/s)².",
"KE = 81 J.",
"Select option D."
] | physics | Answer: 81 J
Steps:
1. KE = ½×2 kg×(9 m/s)².
2. KE = 81 J.
3. Select option D.
Answer: (D) | mechanics |
Three offset phases deliver steady power, running industry smoothly. | null | phy_0656 | concept | en | Why three-phase? | [
"Three offset phases deliver steady power, running industry smoothly.",
"So the answer stands: Three offset phases deliver steady power, running industry smoothly."
] | physics | Answer: Three offset phases deliver steady power, running industry smoothly.
Steps:
1. Three offset phases deliver steady power, running industry smoothly.
2. So the answer stands: Three offset phases deliver steady power, running industry smoothly. | electromagnetism |
Temperature is 298 K. | {
"A": "297 K",
"B": "298 K",
"C": "299 K",
"D": "300 K"
} | phy_0657 | multiple_choice | en | Room temperature is 25 °C. What is it in kelvin? | [
"25 °C + 273.",
"= 298 K.",
"Select option B."
] | physics | Answer: 298 K
Steps:
1. 25 °C + 273.
2. = 298 K.
3. Select option B.
Answer: (B) | thermodynamics |
Zdánlivá hloubka: 60 cm. | null | phy_0658 | worked_example | cs | Předmět leží 90 cm hluboko ve skle (n = 1,5). Spočítej zdánlivou hloubku. | [
"d' = d/n.",
"d' = 90 cm / 1,5.",
"= 60 cm."
] | physics | Answer: Zdánlivá hloubka: 60 cm.
Steps:
1. d' = d/n.
2. d' = 90 cm / 1,5.
3. = 60 cm. | optics |
3rd harmonic: 630 Hz. | null | phy_0659 | worked_example | en | A string's fundamental is 210 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 210 Hz.",
"= 630 Hz."
] | physics | Answer: 3rd harmonic: 630 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 210 Hz.
3. = 630 Hz. | waves |
Nukleonové číslo: 11. | null | phy_0660 | worked_example | cs | Jádro má 5 protonů a 6 neutronů. Spočítej jeho nukleonové číslo. | [
"A = Z+N.",
"A = 5 + 6.",
"= 11."
] | physics | Answer: Nukleonové číslo: 11.
Steps:
1. A = Z+N.
2. A = 5 + 6.
3. = 11. | modern |
Práce: 100 J. | null | phy_0661 | worked_example | cs | Síla 25 N tlačí na dráze 4 m. Spočítej vykonanou práci. | [
"W = F×d.",
"W = 25 N × 4 m.",
"= 100 J."
] | physics | Answer: Práce: 100 J.
Steps:
1. W = F×d.
2. W = 25 N × 4 m.
3. = 100 J. | mechanics |
Voltage: 156 V. | null | phy_0662 | worked_example | en | A current of 13 A flows through 12 Ω. Compute the voltage. | [
"V = I×R.",
"V = 13 A × 12 Ω.",
"= 156 V."
] | physics | Answer: Voltage: 156 V.
Steps:
1. V = I×R.
2. V = 13 A × 12 Ω.
3. = 156 V. | electromagnetism |
Výkon: 70 W. | null | phy_0663 | worked_example | cs | Motor vykoná 700 J práce za 10 s. Spočítej jeho výkon. | [
"P = W/t.",
"P = 700 J / 10 s.",
"= 70 W."
] | physics | Answer: Výkon: 70 W.
Steps:
1. P = W/t.
2. P = 700 J / 10 s.
3. = 70 W. | thermodynamics |
Velikost obrazu ku předmětu. | null | phy_0664 | concept | cs | Co je zvětšení? | [
"Velikost obrazu ku předmětu.",
"Odpověď tedy platí: Velikost obrazu ku předmětu."
] | physics | Answer: Velikost obrazu ku předmětu.
Steps:
1. Velikost obrazu ku předmětu.
2. Odpověď tedy platí: Velikost obrazu ku předmětu. | optics |
The answer is Photoelectric. | {
"A": "Photoelectric",
"B": "Photosynthesis",
"C": "Photography",
"D": "Photocopy"
} | phy_0665 | multiple_choice | en | Choose: what proves photons? | [
"Threshold rules.",
"So: Photoelectric.",
"Select option A."
] | physics | Answer: Photoelectric
Steps:
1. Threshold rules.
2. So: Photoelectric.
3. Select option A.
Answer: (A) | waves |
Lines: 120. | null | phy_0666 | worked_example | en | An atom is excited to level n = 16. Count the spectral lines it can emit. | [
"Pairs: 16×15/2.",
"= 240/2.",
"= 120."
] | physics | Answer: Lines: 120.
Steps:
1. Pairs: 16×15/2.
2. = 240/2.
3. = 120. | modern |
Net force is 24 N. | {
"A": "21 N",
"B": "27 N",
"C": "24 N",
"D": "30 N"
} | phy_0667 | multiple_choice | en | A mass of 8 kg accelerates at 3 m/s². What is the net force? | [
"F = 8 kg × 3 m/s².",
"F = 24 N.",
"Select option C."
] | physics | Answer: 24 N
Steps:
1. F = 8 kg × 3 m/s².
2. F = 24 N.
3. Select option C.
Answer: (C) | mechanics |
Proud je tok náboje za sekundu v ampérech. | null | phy_0668 | concept | cs | Co je proud? | [
"Proud je tok náboje za sekundu v ampérech.",
"Odpověď tedy platí: Proud je tok náboje za sekundu v ampérech."
] | physics | Answer: Proud je tok náboje za sekundu v ampérech.
Steps:
1. Proud je tok náboje za sekundu v ampérech.
2. Odpověď tedy platí: Proud je tok náboje za sekundu v ampérech. | electromagnetism |
Power: 170 W. | null | phy_0669 | worked_example | en | An engine does 1700 J of work in 10 s. Compute its power. | [
"P = W/t.",
"P = 1700 J / 10 s.",
"= 170 W."
] | physics | Answer: Power: 170 W.
Steps:
1. P = W/t.
2. P = 1700 J / 10 s.
3. = 170 W. | thermodynamics |
Magnification is 8×. | {
"A": "7×",
"B": "9×",
"C": "8×",
"D": "10×"
} | phy_0670 | multiple_choice | en | An image forms 80 cm from a lens, object at 10 cm. What is the magnification? | [
"M = 80 cm / 10 cm.",
"M = 8×.",
"Select option C."
] | physics | Answer: 8×
Steps:
1. M = 80 cm / 10 cm.
2. M = 8×.
3. Select option C.
Answer: (C) | optics |
Speed: 2400 m/s. | null | phy_0671 | worked_example | en | A string wave has f = 800 Hz and λ = 3 m. Compute its speed. | [
"v = f×λ.",
"v = 800 Hz × 3 m.",
"= 2400 m/s."
] | physics | Answer: Speed: 2400 m/s.
Steps:
1. v = f×λ.
2. v = 800 Hz × 3 m.
3. = 2400 m/s. | waves |
Mass number: 31. | null | phy_0672 | worked_example | en | A nucleus has 15 protons and 16 neutrons. Compute its mass number. | [
"A = Z+N.",
"A = 15 + 16.",
"= 31."
] | physics | Answer: Mass number: 31.
Steps:
1. A = Z+N.
2. A = 15 + 16.
3. = 31. | modern |
Momentum: 45 kg·m/s. | null | phy_0673 | worked_example | en | A mass of 15 kg moves at 3 m/s. Compute its momentum. | [
"p = m×v.",
"p = 15 kg × 3 m/s.",
"= 45 kg·m/s."
] | physics | Answer: Momentum: 45 kg·m/s.
Steps:
1. p = m×v.
2. p = 15 kg × 3 m/s.
3. = 45 kg·m/s. | mechanics |
Doped silicon conducts controllably, the basis of all electronics. | null | phy_0674 | concept | en | What is a semiconductor? | [
"Doped silicon conducts controllably, the basis of all electronics.",
"So the answer stands: Doped silicon conducts controllably, the basis of all electronics."
] | physics | Answer: Doped silicon conducts controllably, the basis of all electronics.
Steps:
1. Doped silicon conducts controllably, the basis of all electronics.
2. So the answer stands: Doped silicon conducts controllably, the basis of all electronics. | electromagnetism |
Heat needed is 29302 J. | {
"A": "25116 J",
"B": "33488 J",
"C": "29302 J",
"D": "37674 J"
} | phy_0675 | multiple_choice | en | How much heat warms 1 kg of water by 7 K? (c = 4186 J/(kg·K)) | [
"Q = 1 kg × 4186 J/(kg·K) × 7 K.",
"Q = 29302 J.",
"Select option C."
] | physics | Answer: 29302 J
Steps:
1. Q = 1 kg × 4186 J/(kg·K) × 7 K.
2. Q = 29302 J.
3. Select option C.
Answer: (C) | thermodynamics |
1/f rovná se 1/a + 1/a', určuje polohu obrazu. | null | phy_0676 | concept | cs | Proč zobrazovací rovnice? | [
"1/f rovná se 1/a + 1/a', určuje polohu obrazu.",
"Odpověď tedy platí: 1/f rovná se 1/a + 1/a', určuje polohu obrazu."
] | physics | Answer: 1/f rovná se 1/a + 1/a', určuje polohu obrazu.
Steps:
1. 1/f rovná se 1/a + 1/a', určuje polohu obrazu.
2. Odpověď tedy platí: 1/f rovná se 1/a + 1/a', určuje polohu obrazu. | optics |
Speed is 700 m/s. | {
"A": "650 m/s",
"B": "700 m/s",
"C": "750 m/s",
"D": "800 m/s"
} | phy_0677 | multiple_choice | en | A string wave has f = 350 Hz and λ = 2 m. What is its speed? | [
"v = 350 Hz × 2 m.",
"v = 700 m/s.",
"Select option B."
] | physics | Answer: 700 m/s
Steps:
1. v = 350 Hz × 2 m.
2. v = 700 m/s.
3. Select option B.
Answer: (B) | waves |
Its field drags particles giving mass, found in 2012. | null | phy_0678 | concept | en | Why the Higgs? | [
"Its field drags particles giving mass, found in 2012.",
"So the answer stands: Its field drags particles giving mass, found in 2012."
] | physics | Answer: Its field drags particles giving mass, found in 2012.
Steps:
1. Its field drags particles giving mass, found in 2012.
2. So the answer stands: Its field drags particles giving mass, found in 2012. | modern |
Hybnost: 24 kg·m/s. | null | phy_0679 | worked_example | cs | Těleso 8 kg se pohybuje 3 m/s. Spočítej jeho hybnost. | [
"p = m×v.",
"p = 8 kg × 3 m/s.",
"= 24 kg·m/s."
] | physics | Answer: Hybnost: 24 kg·m/s.
Steps:
1. p = m×v.
2. p = 8 kg × 3 m/s.
3. = 24 kg·m/s. | mechanics |
Energy: 1700 J. | null | phy_0680 | worked_example | en | A 100 W heater runs for 17 s. Compute the energy used. | [
"E = P×t.",
"E = 100 W × 17 s.",
"= 1700 J."
] | physics | Answer: Energy: 1700 J.
Steps:
1. E = P×t.
2. E = 100 W × 17 s.
3. = 1700 J. | electromagnetism |
Odpověď je Kelvinova stupnice. | {
"A": "Kelvinova stupnice",
"B": "Celsiova stupnice",
"C": "Beaufortova stupnice",
"D": "Richterova stupnice"
} | phy_0681 | multiple_choice | cs | Vyber: co začíná v nulovém pohybu? | [
"Absolutní nula základem.",
"Tedy: Kelvinova stupnice.",
"Vyber možnost A."
] | physics | Answer: Kelvinova stupnice
Steps:
1. Absolutní nula základem.
2. Tedy: Kelvinova stupnice.
3. Vyber možnost A.
Answer: (A) | thermodynamics |
Apparent depth: 130 cm. | null | phy_0682 | worked_example | en | An object sits 195 cm deep in glass (n = 1.5). Compute the apparent depth. | [
"d' = d/n.",
"d' = 195 cm / 1.5.",
"= 130 cm."
] | physics | Answer: Apparent depth: 130 cm.
Steps:
1. d' = d/n.
2. d' = 195 cm / 1.5.
3. = 130 cm. | optics |
Period is 0.14 s. | {
"A": "0.12 s",
"B": "0.11 s",
"C": "0.14 s",
"D": "0.17 s"
} | phy_0683 | multiple_choice | en | A wave has frequency 7 Hz. What is its period? | [
"T = 1 / 7 Hz.",
"T = 0.14 s.",
"Select option C."
] | physics | Answer: 0.14 s
Steps:
1. T = 1 / 7 Hz.
2. T = 0.14 s.
3. Select option C.
Answer: (C) | waves |
Mirror particles annihilate on contact, fuelling sci-fi and PET scans. | null | phy_0684 | concept | en | What is antimatter? | [
"Mirror particles annihilate on contact, fuelling sci-fi and PET scans.",
"So the answer stands: Mirror particles annihilate on contact, fuelling sci-fi and PET scans."
] | physics | Answer: Mirror particles annihilate on contact, fuelling sci-fi and PET scans.
Steps:
1. Mirror particles annihilate on contact, fuelling sci-fi and PET scans.
2. So the answer stands: Mirror particles annihilate on contact, fuelling sci-fi and PET scans. | modern |
Net force: 28 N. | null | phy_0685 | worked_example | en | A mass of 14 kg accelerates at 2 m/s². Compute the net force. | [
"F = m×a.",
"F = 14 kg × 2 m/s².",
"= 28 N."
] | physics | Answer: Net force: 28 N.
Steps:
1. F = m×a.
2. F = 14 kg × 2 m/s².
3. = 28 N. | mechanics |
One-way valves pass current forward only, rectifying AC into DC. | null | phy_0686 | concept | en | Why diodes? | [
"One-way valves pass current forward only, rectifying AC into DC.",
"So the answer stands: One-way valves pass current forward only, rectifying AC into DC."
] | physics | Answer: One-way valves pass current forward only, rectifying AC into DC.
Steps:
1. One-way valves pass current forward only, rectifying AC into DC.
2. So the answer stands: One-way valves pass current forward only, rectifying AC into DC. | electromagnetism |
If A matches C and B matches C, A matches B, grounding thermometers. | null | phy_0687 | concept | en | Why zeroth law? | [
"If A matches C and B matches C, A matches B, grounding thermometers.",
"So the answer stands: If A matches C and B matches C, A matches B, grounding thermometers."
] | physics | Answer: If A matches C and B matches C, A matches B, grounding thermometers.
Steps:
1. If A matches C and B matches C, A matches B, grounding thermometers.
2. So the answer stands: If A matches C and B matches C, A matches B, grounding thermometers. | thermodynamics |
Magnification: 14×. | null | phy_0688 | worked_example | en | An image forms 140 cm from a lens, object at 10 cm. Compute the magnification. | [
"M = di/do.",
"M = 140 cm / 10 cm.",
"= 14×."
] | physics | Answer: Magnification: 14×.
Steps:
1. M = di/do.
2. M = 140 cm / 10 cm.
3. = 14×. | optics |
Distance: 4760 m. | null | phy_0689 | worked_example | en | Thunder is heard 14 s after lightning. How far away is the storm? (v = 340 m/s) | [
"d = v×t.",
"d = 340 m/s × 14 s.",
"= 4760 m."
] | physics | Answer: Distance: 4760 m.
Steps:
1. d = v×t.
2. d = 340 m/s × 14 s.
3. = 4760 m. | waves |
Přeživší: 800. | null | phy_0690 | worked_example | cs | Vzorek 3200 atomů projde 2 poločasy. Spočítej přeživší. | [
"Půl: 3200 → 1600.",
"Půl: 1600 → 800.",
"= 800."
] | physics | Answer: Přeživší: 800.
Steps:
1. Půl: 3200 → 1600.
2. Půl: 1600 → 800.
3. = 800. | modern |
Work: 260 J. | null | phy_0691 | worked_example | en | A force of 65 N pushes 4 m. Compute the work done. | [
"W = F×d.",
"W = 65 N × 4 m.",
"= 260 J."
] | physics | Answer: Work: 260 J.
Steps:
1. W = F×d.
2. W = 65 N × 4 m.
3. = 260 J. | mechanics |
Power: 588 W. | null | phy_0692 | worked_example | en | A current of 14 A flows through 3 Ω. Compute the dissipated power. | [
"P = I²×R.",
"P = (14 A)² × 3 Ω.",
"= 588 W."
] | physics | Answer: Power: 588 W.
Steps:
1. P = I²×R.
2. P = (14 A)² × 3 Ω.
3. = 588 W. | electromagnetism |
Entropie izolovaných soustav nikdy neklesá. | null | phy_0693 | concept | cs | Co je druhý zákon? | [
"Entropie izolovaných soustav nikdy neklesá.",
"Odpověď tedy platí: Entropie izolovaných soustav nikdy neklesá."
] | physics | Answer: Entropie izolovaných soustav nikdy neklesá.
Steps:
1. Entropie izolovaných soustav nikdy neklesá.
2. Odpověď tedy platí: Entropie izolovaných soustav nikdy neklesá. | thermodynamics |
Time: 12.3 s. | null | phy_0694 | worked_example | en | Light travels 37×10⁸ m. Compute the travel time. (c = 3×10⁸ m/s) | [
"t = d/c.",
"t = 37×10⁸ / 3×10⁸ s.",
"= 12.3 s."
] | physics | Answer: Time: 12.3 s.
Steps:
1. t = d/c.
2. t = 37×10⁸ / 3×10⁸ s.
3. = 12.3 s. | optics |
3rd harmonic: 660 Hz. | null | phy_0695 | worked_example | en | A string's fundamental is 220 Hz. Compute its 3rd harmonic. | [
"f3 = 3×f1.",
"f3 = 3 × 220 Hz.",
"= 660 Hz."
] | physics | Answer: 3rd harmonic: 660 Hz.
Steps:
1. f3 = 3×f1.
2. f3 = 3 × 220 Hz.
3. = 660 Hz. | waves |
Nukleonové číslo je 6. | {
"A": "5",
"B": "7",
"C": "8",
"D": "6"
} | phy_0696 | multiple_choice | cs | Jádro má 3 protonů a 3 neutronů. Jaké je jeho nukleonové číslo? | [
"A = 3 + 3.",
"A = 6.",
"Vyber možnost D."
] | physics | Answer: 6
Steps:
1. A = 3 + 3.
2. A = 6.
3. Vyber možnost D.
Answer: (D) | modern |
Pohybující se hmotnost nese ½mv². | null | phy_0697 | concept | cs | Proč kinetická energie? | [
"Pohybující se hmotnost nese ½mv².",
"Odpověď tedy platí: Pohybující se hmotnost nese ½mv²."
] | physics | Answer: Pohybující se hmotnost nese ½mv².
Steps:
1. Pohybující se hmotnost nese ½mv².
2. Odpověď tedy platí: Pohybující se hmotnost nese ½mv². | mechanics |
Voltage is 35 V. | {
"A": "30 V",
"B": "35 V",
"C": "40 V",
"D": "45 V"
} | phy_0698 | multiple_choice | en | A current of 7 A flows through 5 Ω. What is the voltage? | [
"V = 7 A × 5 Ω.",
"V = 35 V.",
"Select option B."
] | physics | Answer: 35 V
Steps:
1. V = 7 A × 5 Ω.
2. V = 35 V.
3. Select option B.
Answer: (B) | electromagnetism |
It is joules per degree for a whole object, scaling with mass. | null | phy_0699 | concept | en | What is heat capacity? | [
"It is joules per degree for a whole object, scaling with mass.",
"So the answer stands: It is joules per degree for a whole object, scaling with mass."
] | physics | Answer: It is joules per degree for a whole object, scaling with mass.
Steps:
1. It is joules per degree for a whole object, scaling with mass.
2. So the answer stands: It is joules per degree for a whole object, scaling with mass. | thermodynamics |
Apparent depth: 140 cm. | null | phy_0700 | worked_example | en | An object sits 210 cm deep in glass (n = 1.5). Compute the apparent depth. | [
"d' = d/n.",
"d' = 210 cm / 1.5.",
"= 140 cm."
] | physics | Answer: Apparent depth: 140 cm.
Steps:
1. d' = d/n.
2. d' = 210 cm / 1.5.
3. = 140 cm. | optics |
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