WAEC Physics Past Questions & Answers - Page 68

336.

A vector quantity can only be completely described when ……… and …………are mentioned.

A.

Magnitude and motion

B.

Magnitude and direction

C.

Distance and specified displacement

D.

Moment and momentum

Correct answer is B

A vector quantity has both magnitude and direction

There is an explanation video available below.

337.

The resultant force of a couple is ………?

A.

Infinity

B.

Zero

C.

One

D.

Half

Correct answer is B

Note: moment of a couple = force × length (fL)

The tangential force is actingin an opposite direction alongside its length

i.e f1 L1 = f2L2

f2L2 − f1 L1 = 0(i.e Zero)

There is an explanation video available below.

338.

The general gas law can be written as

A.

PV ÷ T = a constant

B.

PV = a constant

C.

v/t = a constant

D.

p/T = a constant

Correct answer is A

Formula for general gas law

V × 1/T × P

N [(PV) ÷ T] = K is constant

There is an explanation video available below.

339.

In an elastic collision

I. Energy is conserved
II. Energy is decreased
III. Energy is increased
IV. Linear momentum conserved

A.

I only

B.

I and IV only

C.

II only

D.

III only

Correct answer is B

In an inelastic collision, linear momentum is conserved and energy is decreased

Momentum and kinetic energy are conserved in elastic collision

There is an explanation video available below.

340.

A stroboscope can be used to make the wave appear ………….

A.

Stationary

B.

In motion

C.

Dipper

D.

Ripple

Correct answer is A

Stroboscope is a scientific instrument used to make a wave appears stationary when used

There is an explanation video available below.