% FILENAME = N7.TXT
% Power calculations
% Release 3, October 2001

%Question: 1
#7.1 A transmitter power amplifier requires 30 mA at 300 volt. The DC input power is: 

300 watt 

9000 watt 

9 watt 

6 watt 

% ans 3 

%Question: 2
#7.2 The DC input power of a transmitter operating at 12 volt and drawing 500 milliamp would be: 

6 watt 

12 watt 

20 watt 

500 watt 

% ans 1 

%Question: 3
#7.3 When two 500 ohm 1 watt resistors are connected in series, the maximum total power that can be dissipated by both resistors is: 

4 watt 

2 watt 

1 watt 

1/2 watt 

% ans 2 

%Question: 4
#7.4 When two 1000 ohm 5 watt resistors are connected in parallel, they can dissipate a maximum total power of: 

40 watt 

20 watt 

10 watt 

5 watt 

% ans 3 

%Question: 5
#7.5 The current in a 100 kilohm resistor is 10 mA. The power dissipated is: 

1 watt 

10 watt 

100 watt 

10,000 watt 

% ans 2 

%Question: 6
#7.6 A current of 500 milliamp passes through a 1000 ohm resistance. The power dissipated is: 

0.25 watt 

2.5 watt 

25 watt 

250 watt 

% ans 4 

%Question: 7
#7.7 A 20 ohm resistor carries a current of 0.25 ampere. The power dissipated is: 

1.25 watt 

5 watt 

2.50 watt 

10 watt 

% ans 1 

%Question: 8
#7.8 If 200 volt is applied to a 2000 ohm resistor, the resistor will dissipate: 

20 watt 

30 watt 

10 watt 

40 watt 

% ans 1 

%Question: 9
#7.9 The power delivered to an antenna is 500 watt. The effective antenna resistance is 20 ohm. The antenna current is: 

25 amp 

2.5 amp 

10 amp 

5 amp 

% ans 4 

%Question: 10
#7.10 The unit for power is the: 

ohm 

watt 

ampere 

volt 

% ans 2 

%Question: 11
#7.11 The following two quantities should be multiplied together to find power: 

resistance and capacitance 

voltage and current 

voltage and inductance 

inductance and capacitance 

% ans 2 

%Question: 12
#7.12 The following two electrical units multiplied together give the unit "watt": 

volt and ampere 

volt and farad 

farad and henry 

ampere and henry 

% ans 1 

%Question: 13
#7.13 The power dissipation of a resistor carrying a current of 10 mA with 10 volt across it is: 

0.01 watt 

0.1 watt 

1 watt 

10 watt 

% ans 2 

%Question: 14
#7.14 If two 10 ohm resistors are connected in series with a 10 volt battery, the battery load is: 

5 watt 

10 watt 

20 watt 

100 watt 

% ans 1 

%Question: 15
#7.15 Each of 9 resistors in a circuit is dissipating 4 watt. If the circuit operates from a 12 volt supply, the total current flowing in the circuit is: 

48 ampere 

36 ampere 

9 ampere 

3 ampere 

% ans 4 

%Question: 16
#7.16 Three 18 ohm resistors are connected in parallel across a 12 volt supply. The total power 
dissipation of the resistor load is: 

3 watt 

18 watt 

24 watt 

36 watt 

% ans 3 

%Question: 17
#7.17 A resistor of 10 kilohm carries a current of 20 mA. The power dissipated in the resistor is: 

2 watt 

4 watt 

20 watt 

40 watt 

% ans 2 

%Question: 18
#7.18 A resistor in a circuit becomes very hot and starts to burn. This is because the resistor is dissipating too much: 

current 

voltage 

resistance 

power 

% ans 4 

%Question: 19
#7.19 A current of 10 ampere rms at a frequency of 50 Hz flows through a 100 ohm resistor. The 
power dissipated is: 

500 watt 

707 watt 

10,000 watt 

50,000 watt 

% ans 3 

%Question: 20
#7.20 The voltage applied to two resistors in series is doubled. The total power dissipated will: 

increase by four times 

decrease to half 

double 

not change 

% ans 1