WAEC Physics Past Questions & Answers - Page 264

1,316.

If the current in the resistor R in diagram above is 0.05A, calculate the p.d. across the inductor.

A.

2.5V

B.

25.0V

C.

49.0V

D.

50.0V

E.

250.0V

Correct answer is A

V= i × \(_l\)

X\(_l\) = inductive reactance → 50

I = current → 0.05A
V = 0.05 × 50

V = 2.5volt

1,317.

Calculate the inductive reactance of the circuit shown above.

A.

50.00

B.

5.00

C.

0.50

D.

0.05

E.

0.02

Correct answer is A

No explanation has been provided for this answer.

1,318.

Calculate the electric potential at a distance of 20.0cm from a point charge of 0.015C placed in air of permittivity (Take 1/4πεo as 9.0 x 109 Nm2C2)

A.

3.40x106V

B.

6.75x105V

C.

6.75x1012V

D.

3.40x105V

E.

8.30 x 102V

Correct answer is B

No explanation has been provided for this answer.

1,319.

Calculate the inductance L of the coil in the circuit shown above.

A.

14.4H

B.

3.8H

C.

0.6H

D.

0.4H

E.

0.2H

Correct answer is C

XL = \(\frac{V}{I} = \frac{240}{2} = 120\Omega\)

L = \(\frac{X_L}{2 \pi f}\)

= \(\frac{120 \times \pi}{2 \times \pi \times 100}\)

= 0.6H

1,320.

A balloon containing 546cm3 of air is heated from 0oC to 10oC. If the pressure is kept constant, what will be its volume at 10oC?

A.

526cm3

B.

546cm3

C.

556cm

D.

566cm3

E.

819cm3

Correct answer is D

No explanation has been provided for this answer.