WAEC Physics Past Questions & Answers - Page 72

356.

Which of the following conditions occur at resonance in a series RLC circuit? i. Impedance equals resistance ii. Current is maximum iii. Reactance is maximum iv. Current and voltage are 90° out of phase

A.

i and ii only

B.

i and iii only

C.

i, ii and iii only

D.

i, ii, iii and iv

Correct answer is A

conditions for the occurrence of resonance in a series RLC circuit are i) impedance is at minimum ie when inductive and capacitive reactances are equal ii) when current is maximum

357.

The energy stored in a simple cell is

A.

electrical

B.

nuclear

C.

thermal

D.

chemical

Correct answer is D

No explanation has been provided for this answer.

358.

In an ac circuit when the supply voltage frequency is equal to the resonant frequency, the current

A.

leads the supply voltage by 90o

B.

lags behind the supply voltage by 90o

C.

leads the supply voltage by 45o

D.

is in phase with the supply voltage

Correct answer is D

No explanation has been provided for this answer.

359.

The region around a magnet in which magnetic force can be expressed is known as

A.

declination

B.

flux density

C.

field

D.

flux

Correct answer is C

No explanation has been provided for this answer.

360.

An ammeter can be adapted to measure potential difference by using a

A.

shunt

B.

multiplier

C.

rheostat

D.

resistance box

Correct answer is B

No explanation has been provided for this answer.