WAEC Physics Past Questions & Answers - Page 276

1,376.

A point charge of 1.0 x 10-7 C experiences force of 0.01 N in a uniform electric field. Calculate the magnitude of the strength of the field

A.

106 Vm-1

B.

105 Vm-1

C.

10-5 Vm-1

D.

102 Vm-1

E.

109 Vm-1

Correct answer is B

F = qE

E =
F/q
=
0.01/1.0 x 10-7
= 105Vm-1

1,377.

In a purely resistive a.c. circuit, the current I = Io sin wt and voltage, V = Vo sin wt. Calculate the instantaneous power dissipated in the circuit in time t.

A.

Io Vo

B.

2Io Vosin wt

C.

(Io Vo)/2

D.

Io Vo sin2wt

E.

I2o V2o

Correct answer is D

No explanation has been provided for this answer.

1,380.

What is the gravitational potential due to a point mass m at a distance from it? (G = gravitational constant)

A.

-Gm2/r2

B.

-Gm2/r

C.

–Gm/Gr2

D.

–Gm/r

E.

–Gm/2

Correct answer is D

No explanation has been provided for this answer.