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JAMB Physics Past Questions & Answers - Page 207

1,031.

A vapour is said to be saturated when?

A.

more molecules return to the liquid than leave it

B.

a dynamic equilibrium exists between the liquid molecules and the vapour molecules at a given temperature

C.

the vapour pressure is atmospheric

D.

the temperature of the vapour varies

E.

all molecules are moving with the same speed

Correct answer is B

A vapor saturated is said to be in a dynamic equilibrium with its own liquid

1,032.

The ice and steam points of mercury-in-glass thermometer of centigrade scale and of uniform bore correspond respectively to 3cm and 19cm lengths of the mercury thread when the length is 12cm, the temperature is

A.

32oC

B.

48oC

C.

56oC

D.

65oC

E.

75oC

Correct answer is C

steam point - ice point in oC = 100oC - 0oC

= 1.9cm - 3cm = 16cm

12cm = 3cm = 9cm

916 x 100oC = 56.25oC

= 56oC

1,033.

A 10g mass placed on the pan of a spring balance causes an extension of 5cm. If a 15g mass is placed on the pan of the same spring balance, the extension is

A.

3.3cm

B.

6.5cm

C.

7.5cm

D.

10.8cm

E.

15.0cm

Correct answer is C

F α e and m α F

m1e1 = m2e2

105 = 15e2

e2 = 7.5cm

1,034.

The point beyond which a stretched spring does not return to its original length is called the

A.

breaking point

B.

elastic limit

C.

spring constant

D.

elasticity point

E.

release point

Correct answer is B

No explanation has been provided for this answer.

1,035.

A hydrometer is an instrument for measuring the

A.

depth of water in a vessel

B.

relative density of a liquid by the method of flotation

C.

relative density of a liquid by finding the apparent loss in weight

D.

relative humidity of the air

E.

atmospheric pressure when the air is humid

Correct answer is B

No explanation has been provided for this answer.