WAEC Physics Past Questions & Answers - Page 30

146.

When two cells of negligible internal resistances and equal e.m.f. denoted by E\(_1\) and E\(_2\) are connected in parallel, combined e.m.f. E is given by
 

A.

E = E\(_1\) + E\(_2\)

B.

E = \(\frac{E_1}{E_2}\)

C.

\(\frac{1}{E} = \frac{1}{E_1} + \frac{1}{E_2}\)

D.

E = E\(_1\) = E\(_2\)

Correct answer is C

 If two cells of equal emf s are connected in parallel then the effective emf is equal to the emf of any one of the cells. 

147.

In photoelectric effect, the number of electrode emitted per second from a metallic surface is proportional to the

A.

intensity of the incident radiation

B.

frequency of the incident radiation

C.

energy of the incident radiation

D.

work function of the metal.

Correct answer is A

No explanation has been provided for this answer.

148.

The vacuum between the double walls of a thermos flask reduces heat loss through

A.

conduction and radiation

B.

convection and conduction

C.

radiation only

D.

conduction only

Correct answer is B

No explanation has been provided for this answer.

149.

Which of the following units is not fundamental?

A.

Metre

B.

Kilogram

C.

Joule

D.

Candela

Correct answer is C

No explanation has been provided for this answer.

150.

A luminous object is one that

A.

gives off dim blue-green light only in the dark.

B.

gives out light of its own

C.

shines by reflected light only

D.

glows only in the presence of light

Correct answer is B

No explanation has been provided for this answer.