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WAEC Physics Past Questions & Answers - Page 159

791.

The distance between two points in phase on a progressive wave is 5cm. If the sped of the wave is 0.2ms-1, calculate its period

A.

4.00s

B.

2.50s

C.

0.25s

D.

0.04s

Correct answer is C

F = vλ=0.25×102=4Hz

T = 1f=14=0.25s

792.

Which of the following statements about a progressive mechanical wave is correct?

A.

it can be a plane polarised

B.

its energy is localised at specific points of its profile

C.

it does not require a material medium for its propagation

D.

its frequency remains constant as it travels between different media

Correct answer is D

No explanation has been provided for this answer.

793.

The pressure exerted by a given mass of gas in a container

A.

decreases if the container is heated

B.

increases if the molecules of the gas move faster

C.

increases if the container is doubled

D.

decreases as the kinetic energy of the gas molecules inceases

Correct answer is B

No explanation has been provided for this answer.

794.

Which of the following statements is correct?

A.

the density of a liquid decreases when it expands

B.

the density of a liquid increases when the liquids are heated

C.

the real expansivity of a liquid is less than its apparent expansivity

D.

a liquid changes to solid when heated to a sufficiently high temperature

Correct answer is A

No explanation has been provided for this answer.

795.

Which of the following statements about boiling and evaporation at atmospheric pressure is correct?

A.

evaporation and boiling of water take place at 100o

B.

evaporation of water takes place at a temperature greater than 100oC, while boiling takes place at 100oC

C.

evaporation of water takes place at 100oC while boiling takes place at a higher temperature

D.

boiling takes place at 100o while evaporation my take place at temperatures lower than 100oC

Correct answer is D

No explanation has been provided for this answer.