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Chapter 3. 3. WORK, POWER AND, ENERGY. 3.1. WORK, ELECTRICAL POWER, MECHANICAL POWER, AND ENERGY. MCQs

1. . Product of force and distance is called:

(A) Power


(B) Work done


(C) Speed


(D) Velocity




2. . Trade unit of electrical energy:

(A) KWH


(B) WH


(C) H.P


(D) B.H.P




3. . If a 100W lamp is burned for 15 hours, the energy consumed is:

(A) 0.5 unit


(B) 1.5 unit


(C) 6.67 unit


(D) 15 unit




4. . A potential difference of 20V is applied across a resistor of 2.5 ohms. The power will be:

(A) 170 watts


(B) 180 watts


(C) 190 watts


(D) 160 watts




5. . The unit of work is the joule. Another physical quantity with the same unit is:

(A) Power


(B) Velocity


(C) Energy


(D) Force




6. . Energy in the form of heat and light is obtained from:

(A) Biomass


(B) Fossil fuels


(C) Sun


(D) Wind




7. . A bullet fired from a gun can pierce a target due to its:

(A) Mechanical energy


(B) Heat energy


(C) Kinetic energy


(D) Acceleration




8. . A capacitor stores which type of energy?

(A) Kinetic energy


(B) Vibrational energy


(C) Potential energy


(D) Heat energy




9. . Formula of work done:

(A) Work done = force × displacement


(B) Work done = force × velocity


(C) Work done = pressure × displacement


(D) Work done = mass × acceleration




10. . Which of the following is not an expression of power?

(A) P = VI


(B) P = I²R


(C) P = V²/R


(D) P = I/R




11. . The SI unit of power is:

(A) kW (kilo-watt)


(B) J/s (joules per second)


(C) Ws (watt-second)


(D) J/h (joules per hour)




12. . The SI unit of work is:

(A) Joule


(B) Volt


(C) g/cm


(D) Watt




13. . The rate of doing work is called:

(A) Power


(B) Energy


(C) Watt


(D) Current




14. . The capacity of doing work is called:

(A) Power


(B) Energy


(C) Watt


(D) Current




15. . The unit of electrical power is:

(A) Volt


(B) Coulomb


(C) Watt


(D) Current




16. . Three hundred joules of energy are consumed in 15 s. The power is:

(A) 2,000 W


(B) 2 W


(C) 20 W


(D) 200 W




17. . Watt is equal to:

(A) Joule per second


(B) Meter per second


(C) Ampere per second


(D) Farad per second




18. . B.T.U stands for:

(A) British Thermal Unit


(B) Big Thermal Unit


(C) Both Thermal Unit


(D) Bit Thermal Unit




19. . One kilo calorie is equal to:

(A) 3187 J


(B) 4100 J


(C) 4187 J


(D) 1 B.T.U




20. . Efficiency is the ratio of:

(A) Input / Output


(B) Output / Input


(C) Output / Losses


(D) Input / Losses




21. . Thermal efficiency is the ratio of:

(A) Heat actually utilized / Total heat produced electrically


(B) Total heat produced electrically / Heat actually utilized


(C) Heat actually utilized × Total heat produced electrically


(D) None of them




22. . Electrical energy bill is calculated with:

(A) kWh × Rate/unit


(B) Wh × Rate/unit


(C) W sec × Rate/unit


(D) kW × Rate/unit




23. . One Horse Power (HP) = _______ Watt:

(A) 646


(B) 764


(C) 746


(D) 546




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