ECAT Pakistan · Physics

Electricity, Magnetism and Modern Physics

24 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 24 questions

  1. A body moves in a circle of radius 10 m at 30 m/s. What is its centripetal acceleration?
  2. A body slides down a smooth slope at an angle whose sine is 4/5. What is its acceleration? (take g = 10 m/s²)
  3. A 40 kg load hangs 2 m from the pivot of a light uniform lever. What force at 0.5 m on the other side of the pivot balances it? (take g = 10 m/s²)
  4. A body of volume 0.002 m³ is fully immersed in a liquid of density 1200 kg/m³. What is the upthrust? (take g = 10 m/s²)
  5. A 5 kg trolley moving at 6 m/s hits a stationary 1 kg trolley and they stick together. What is their common speed?
  6. A body moving at 4 m/s accelerates uniformly at 8 m/s² for 8 s. What is its final speed?
  7. What force gives a mass of 9 kg an acceleration of 5 m/s²?
  8. What is the kinetic energy of a 4 kg body moving at 13 m/s?
  9. How much gravitational potential energy does a 3 kg mass gain when lifted 23 m? (take g = 10 m/s²)
  10. A force of 100 N acts at 60° to the horizontal and moves a body 9 m along the horizontal. How much work does it do?
  11. A machine does 4500 J of work in 10 s. What is its power?
  12. A machine takes in 800 J of energy and gives out 160 J of useful work. What is its efficiency?
  13. A force of 200 N acts on an area of 0.1 m². What pressure does it exert?
  14. What is the pressure due to a column of liquid of density 1030 kg/m³ and depth 2 m? (take g = 10 m/s²)
  15. A wave has a frequency of 100 Hz and a wavelength of 2 m. What is its speed?
  16. A source vibrates with a frequency of 5 Hz. What is its period?
  17. A spring of constant 500 N/m is stretched by 0.3 m. How much energy is stored in it?
  18. What is the period of a simple pendulum of length 1.6 m? (take g = 10 m/s²)
  19. Two resistors of 12 Ω and 4 Ω are connected in parallel. What is their combined resistance?
  20. A device on a 24 V supply draws 2 A. What is its power?
  21. How much energy in kWh does a 3000 W heater use in 2 hours?
  22. A transformer has 1000 turns on the primary coil and 20000 turns on the secondary. The primary voltage is 110 V. What is the secondary voltage?
  23. How much heat is needed to warm 0.5 kg of water by 10 °C? (specific heat capacity of water = 4200 J/(kg °C))
  24. A gas in a rigid container is at 100 kPa and 400 K. It is heated to 600 K. What is the new pressure?

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