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JAMB Physics Past Questions & Answers - Page 103

511.

In the diagram above, which of the following velocity-time graphs shows uniform acceleration of a body from rest?

Correct answer is C

See the velocity-time graph.

512.

If the magnification of a virtual image formed by an object 10cm from a convex less is 3, then the focal length of the lens is

10cm

20cm

25cm

15cm

View answer & explanation

Correct answer is D

M = $\frac{v}{u}$ = 3 = $\frac{v}{30}$ . V = 30m

$\frac{1}{u}$ + $\frac{1}{v}$ = $\frac{1}{f}$ = $\frac{1}{10}$ - $\frac{1}{30}$ = $\frac{1}{f}$

$\frac{3 - 1}{30}$ = $\frac{1}{f} f = \(\frac{30}{2}$ = 15cm

513.

Boiling occurs when the vapour pressure of a liquid is

At the evaporation point

Less than the atmospheric pressure

Greater than the atmospheric pressure

Equal to the atmospheric pressure

View answer & explanation

Correct answer is D

No explanation has been provided for this answer.

514.

The impulse of a force is deduced from Newton's second law as

F = ma

F = m( $\frac{v - u}{t}$

F = mg

F = mv - mu

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.

515.

A manometer is an instrument used for measuring

Relative density of liquid

Pressure in liquids and gases

Humidity

Atmospheric pressure

View answer & explanation

Correct answer is B

a manometer is used to measure pressure in liquids and gases. Manometer gauges measure the pressure of gases and vapors from atmospheric to about 1 Pa by balancing the force exerted by the gas or vapor against the weight of a column of liquid, usually mercury, water, or oil.