% FILENAME = N8.TXT
% Alternating Current
% Release version 2, January 2000

%Question: 1
#8.1 An 'alternating current' is so called because: 

it reverses direction periodically 

it travels through a circuit using alternate paths 

its direction of travel is uncertain 

its direction of travel can be altered by a switch 

% ans 1 

%Question: 2 
#8.2 The time for one cycle of a 100 Hz signal is: 

1 second 

0.01 second 

0.0001 second 

10 seconds 

% ans 2 

%Question: 3 
#8.3 A 50 hertz current in a wire means that: 

a potential difference of 50 volts exists across the wire 

the current flowing in the wire is 50 amperes 

the power dissipated in the wire is 50 watts 

a cycle is completed 50 times in each second 

% ans 4 

%Question: 4 
#8.4 The current in an AC circuit completes a cycle in 0.1 second. So the frequency is: 

1 Hz 

10 Hz 

100 Hz 

1000 Hz 

% ans 2 

%Question: 5 
#8.5 An impure signal is found to have 2 kHz and 4 kHz components. This 4 kHz signal is: 

a fundamental of the 2 kHz signal 

a sub-harmonic of 2 kHz 

the DC component of the main signal 

a harmonic of the 2 kHz signal

% ans 4 

%Question: 6 
#8.6 The correct name for the equivalent of 'one cycle per second' is one: 

henry 

volt 

hertz 

coulomb 

% ans 3 

%Question: 7 
#8.7 One megahertz is equal to: 

0.0001 Hz 

100 kHz 

1000 kHz 

10 Hz 

% ans 3 

%Question: 8 
#8.8 One GHz is equal to: 

1000 kHz 

10 MHz 

100 MHz 

1000 MHz 

% ans 4

%Question: 9 
#8.9 The 'rms value' of a sine-wave signal is: 

half the peak voltage 

1.414 times the peak voltage 

the peak-to-peak voltage 

0.707 times the peak voltage

% ans 4 

%Question: 10 
#8.10 A sine-wave alternating current of 10 ampere peak has an rms value of: 

5 amp 

7.07 amp 

14.14 amp 

20 amp 

% ans 2