JAMB Physics Past Questions & Answers - Page 216

1,076.

An object 15cm high is 30cm from pin-hole camera. If the height of the image formed at the back of the camera is 10cm, the image distance is

A.

20cm

B.

45cm

C.

54cm

D.

63cm

E.

70cm

Correct answer is A

\(\frac{\text{image height}}{\text{object height}}\) = \(\frac{\text{image distance}}{\text{object distance}}\)

\(\frac{10}{15}\) = \(\frac{\text{image distance}}{30}\)

image distance = 20cm

1,077.

250g of lead at 170oC is dropped into 100g of water at 0oC. If the final temperature is 12oC, the specific heat of lead is (specific heat of water is 4,200J/kgoC)

A.

39.5J/kgoC

B.

50.4J/kgoC

C.

127.6J/kgoC

D.

154.6J/kgoC

E.

173.4J/kgoC

Correct answer is C

Heat lost = heat gained

0.25 x C1 x (170 - 12) = 0.1 x 4200 x (12 - 0)

C1 = 127.6J/kgoC

1,078.

Which of the following statements is NOT true? Thermostats are used to control the temperature of

A.

pressure cookers

B.

laundry irons

C.

hot water storage tanks

D.

aquaria for tropical fish

E.

heated apartments

Correct answer is A

No explanation has been provided for this answer.

1,079.

The accurate measurement of the relative density of substances in powder or granular form can be done using a beam balance and a

A.

pipette

B.

burette

C.

measuring cylinder

D.

density

E.

bottle

Correct answer is E

No explanation has been provided for this answer.

1,080.

Which of the following machines does NOT apply the lever principle?

A.

claw hammer

B.

wheel barrow

C.

single moving pulley

D.

sugartongs

E.

nutcrackers

Correct answer is C

No explanation has been provided for this answer.