Physics Past Questions, Answers, And Explanations - Physics

Physics Questions

Question 56:

JAMB 1979

Which of the following statements defines correctly the efficiency of a machine?

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A The load carried by the machine divided by effort required in carrying the load
B The distance moved by the load divided by the distance moved by the effort
C The useful work done by the machine divided by the total work put into the machine
D The movement of the load divided by the movement of the effort about the same point
E The temperature at the end of the application of the machine divided by the initial temperature

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Question 57:

JAMB 1979

A 500kg car which was initially at rest travelled with an acceleration of 5m sec-2, its kinetic energy after 4 seconds was

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A 105J
B 2.5 x 103J
C 2 x 103J
D 5 x 103J
E 5 x 105J`

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Question 58:

JAMB 1979

Two closed vessels contain equal volumes of boiling water and are identical except that one is blackened on the outside while the other is polished. Which of the following is correct?

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A The polished vessel will cool faster because a polished surface is a good radiator
B The polished vessel will cool faster because it will absorbe less heat from the room
C The black vessel will cool faster because it is a better conductor of heat
D The polished vesselwill cool faster because it reflects heat better
E The black vessel will cool faster because a black surface radiates heat faster than a polished one

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Question 59:

JAMB 1979

The temperature at which the water vapour present in the air saturates the air and begins to condense is known as

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