subject

Power

Physics ⇒ Mechanics

Power starts at 8 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Power. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.
See sample questions for grade 10
Explain the difference between power and energy.
Explain why two people doing the same work in different times have different power outputs.
What is the SI unit of power?
A 60 W lamp is left on for 10 hours. How much energy does it use in kilowatt-hours?
A 75 kg athlete runs up a 10 m high hill in 20 seconds. Calculate the average power developed. (Take g = 10 m/s²)
A car engine does 30,000 J of work in 20 seconds. What is the power output of the engine?
A light bulb is rated at 60 W. How much energy does it use in 2 hours?
A machine does 2000 J of work in 10 seconds. What is its power output?
Which of the following best describes average power? (1) Total work done divided by total time taken (2) Maximum work done at any instant (3) Total energy divided by mass (4) Force multiplied by acceleration
Which of the following devices is used to measure power directly? (1) Ammeter (2) Voltmeter (3) Dynamometer (4) Thermometer
Which of the following is a correct expression for instantaneous power? (1) P = F × v (2) P = m × a (3) P = F / v (4) P = v / F
Which of the following is NOT a unit of power? (1) Watt (2) Joule/second (3) Newton-meter/second (4) Joule
Fill in the blank: 1 horsepower (hp) is equal to ______ watts.
Fill in the blank: The power developed by a force acting on a moving object is given by P = ______ × v.
Power can be expressed as the product of force and ______.
Power is defined as the rate at which ______ is done.
True or False: If two machines do the same work, the one that does it faster has more power.
True or False: Power can be increased by doing the same amount of work in less time.
True or False: Power is always positive.
True or False: The power output of a machine can never exceed the power input.