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JAMB Physics Past Questions & Answers - Page 213

1,061.

The tyre pressure of a car was found to be 150cmHg in the morning at a temperature of 27°C. Hard driving in the afternoon raised the temperature of the tyres to 57°C. The tyre pressure by the afternoon would be?

A.

increased by 15.0cm Hg

B.

decreased by 15.0cm Hg

C.

increased by 22.50cm

D.

decreased by 22.50cm Hg

E.

remained constant

Correct answer is A

P1T1 = P2T2 at constant volume

15027+273 = P157+273

P2 = 165cmHg

1,062.

When equal weights of iron and water are subjected to equal supply of heat, it is found that the piece of iron become more hotter than water after a short time because

A.

the specific heat of iron is higher than that of water

B.

iron is in solid form

C.

water is in liquid form

D.

the specific heat of water is higher than that of iron

E.

the specific heat of iron is infinite

Correct answer is D

No explanation has been provided for this answer.

1,064.

A man stands on a spring scale placed in a lift. The lift descends at constant velocity. As a result, the scale reads a weight

A.

greater than the weight of the man

B.

the same as the weight of the man

C.

of zero

D.

less than the weight of the man

E.

greater than the weight of the man by 1kg

Correct answer is B

No explanation has been provided for this answer.

1,065.

The hatch door of a submarine has an area of 0.5m2. The specific gravity of sea water is 1.03. Assume that g = 10ms-1,and neglect the atmospheric pressure. The force exerted by the sea water on the hatch door at a depth of 200m is

A.

1.03 x 105N

B.

1.03 x 104Nm-2

C.

1.06 x 105Nm-2

D.

2.06 x 106N

E.

1.03 x 103N

Correct answer is E

Pressure in liquid = e x h x g

Pressure in solid = forcearea

forcearea = e x h x g

force = 0.5 x 10 x 200 x 1.03

= 1030N