JAMB Physics Past Questions & Answers - Page 246

1,226.

The specific latent heat of fusion of lead is the amount of heat required to

A.

melt lead at its melting point

B.

heat a unit mass of lead through 1oC

C.

change the state of a unit mass of lead at its melting point

D.

change the state of a unit mass of lead at its boiling point

Correct answer is C

No explanation has been provided for this answer.

1,227.

The mode of heat transfer which does not require a material medium is

A.

conduction

B.

radiation

C.

convection

D.

propagation

Correct answer is B

No explanation has been provided for this answer.

1,229.

A rectangular tank contains water to a depth of 2m, if the base is 4m x 3m, calculate the force on the base (Density of water = 103kgm-3, g = 10ms-2)

A.

1.4 x 102N

B.

24 x 104N

C.

2.0 x 104N

D.

1.7 x 103N

Correct answer is B

Volume = 2 x 4 x 3 = 24m3

mass = V x D = 24 x 103

F = mg

= 24 x 103 x 10

= 24 x 104

1,230.

A constant force of magnitude F acts on an object of mass 0.04kg initially at rest at a point O. if the speed of the object when it has moved 50m from O is 500ms-1, what is the value of F?

A.

0.4N

B.

100.0N

C.

250.0N

D.

1000.0N

Correct answer is B

F = ma and V2 = U2 + 2aX

F = m\(\frac{(V^2 - U^2)}{2X}\)

= 0.04\(\frac{(500^2 - 0^2)}{2 \times 50}\)

F = 100N