Question 3.
- Define electric power.
- A 4kW microwave is operated by connecting it to 240V mains. Calculate:
(i) its resistance;
(ii) the current drawn from the mains.
(c) In Fig. 2, M and N are transistor amplifier circuit diagrams.
Use Fig. 2 to complete Table 2.
Table 2
|
M |
N |
Configuration |
|
|
Type of transistor |
|
|
Function of Vcc |
|
|
Observation
The expected answers were:
(a) Electric power is the time rate of doing work/dissipating energy in electric circuit.
Where I = current,
V = voltage and
R = resistance.
(b) (i)
OR 
OR 
R = 14.4Ω
(ii) 
OR 
OR 
I = 16.67A
(c) Table 2
|
M |
N |
Configuration |
Common base |
Common emitter |
Type of transistor |
PNP |
NPN |
Function of Vcc |
Supplies reverse bias voltage |
Supplies reverse bias voltage |
It was reported that majority of the candidates who attempted Question 3 responded well.