1995 - WAEC Physics Past Questions and Answers - page 5
41
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
correct option: a
Users' Answers & Comments42
A capacitor of capacitance 25μF is connected to an a.c. power source of frequency 200 Hz. Calculate the reactance of the capacitor
A
0.01
B
0.02
C
50.00
D
100.00
correct option: d
Users' Answers & Comments43
The energy stored in a capacitor of capacitance 5μF is 40J. Calculate the voltage applied across its terminals?
A
4000V
B
200V
C
16V
D
6V
correct option: a
\(E = \frac{CV^{2}}{2}\)
\(V^{2} = \frac{2E}{C}\)
\(V^{2} = \frac{2\times 40}{5 \times 10^{-6}}\)
\(V^{2} = 16 \times 10^{6}\)
\(V = 4 \times 10^{3} = 4000v\)
44
The effective capacitance between points X and Y in the diagram below is 1.0μF, What is the value of the capacitance C, measured in micro-farad?
A
5.0μF
B
4.0μF
C
3.0μF
D
1.0μF
correct option: d
Users' Answers & Comments45
Calculate the quantity charge flowing through a conductor if a current of 10A passes through the conductor for 10s.
A
100C
B
20C
C
15C
D
10C
correct option: a
Users' Answers & Comments46
An alternating current, having the waveform shown in the diagram above, is represented by the equation x = Xo sinwt. Which of the following represents Xo?
A
OS
B
OR
C
PQ
D
RT
correct option: c
Users' Answers & Comments47
What is the potential difference between X and Y in the diagram above if the battery is of negligible internal resistance
A
12.5V
B
5.8V
C
5.0V
D
3.0V
correct option: d
Users' Answers & Comments48
Calculate the current in the 30 resistor in the diagram above if the battery is of negligible internal resistance
A
0.3A
B
0.4A
C
1.0A
D
1.5A
correct option: c
Users' Answers & Comments49
Which of the following is a wind instrument?
A
Guitar
B
Organ
C
Violin
D
Piano
correct option: b
Users' Answers & Comments50
A cell of e.m.f 1.5V and internal resistance 2.552 is connected in series with an ammeter resistance 0.50 and a load of resistance 7.00. Calculate the current in the circuit
A
0.15A
B
0.20A
C
2.1OA
D
3.00A
correct option: a
Users' Answers & Comments