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WAEC Physics Past Questions & Answers - Page 17

81.

Which of the following statement(s) is/are correct about a fixed mass of gas compressed in an inexpansible container;

I. The average speed of the molecules increases

II. The temperature of the gas increases

III. The molecules hit the walls of the container more often than before the compression 

A.

I only

B.

I and II only

C.

I, II, and III only

D.

I and III

Correct answer is C

The kinetic-molecular theory of gases assumes that ideal gas molecules:

(1) are constantly moving;

(2) have negligible volume;

(3) have negligible intermolecular forces;

(4) undergo perfectly elastic collisions; and

(5) have an average kinetic energy proportional to the ideal gas's absolute temperature.

82.

The joule is equivalent to?

A.

Kg m2 s1

B.

Kg2 m s2

C.

Kg m2 s2

D.

Kg m s1

Correct answer is C

Joule as the unit of work done or energy used.

Force = mass × acceleration
 Work = Force × Distance
 Work = mass x acceleration x distance

Joule = kg × ms2 × m

→ kg m2 s2 

83.

The correct relationship between the displacement, s, of a particle initially at rest in a linear motion and the time, t, is?

A.

s α t2

B.

s α t1

C.

s α t

D.

s α t2

Correct answer is D

Mathematically;  S = vt + 12 at2

: S ∝ t2

84.

Which of the illustrated graphs above represents a body moving with uniform retardation?

A.

A

B.

B

C.

C

D.

D

Correct answer is D

If a body moves with uniform retardation, the velocity-time graph is a straight line.

85.

Suppose three identical steel balls Q, R, and S, are placed on an undulating ground as illustrated in the diagram above. Which of the balls is/are in neutral equilibrium?

A.

S only

B.

Q only

C.

R only

D.

Q and S only

Correct answer is A

A system is in neutral equilibrium if its equilibrium is independent of displacements from its original position. A marble S on a flat horizontal surface is an example.