Questions - Alternating Current

Question file 8


  1. An 'alternating current' is so called because:                  STUDY NOTES    
    1. it reverses direction periodically
    2. it travels through a circuit using alternate paths            QUESTIONS WITHOUT ANSWERS 
    3. its direction of travel is uncertain
    4. its direction of travel can be altered by a switch
    ========= Answer is a =========
  2. The time for one cycle of a 100 Hz signal is:
    1. 1 second
    2. 0.01 second
    3. 0.0001 second
    4. 10 seconds
    ========= Answer is b =========
  3. A 50 hertz current in a wire means that:
    1. a potential difference of 50 volts exists across the wire
    2. the current flowing in the wire is 50 amperes
    3. the power dissipated in the wire is 50 watts
    4. a cycle is completed 50 times in each second
    ========= Answer is d =========
  4. The current in an AC circuit completes a cycle in 0.1 second. So the frequency is:
    1. 1 Hz
    2. 10 Hz
    3. 100 Hz
    4. 1000 Hz
    ========= Answer is b =========
  5. An impure signal is found to have 2 kHz and 4 kHz components. This 4 kHz signal is:
    1. a fundamental of the 2 kHz signal
    2. a sub-harmonic of 2 kHz
    3. the DC component of the main signal
    4. a harmonic of the 2 kHz signal
    ========= Answer is d =========
  6. The correct name for the equivalent of 'one cycle per second' is one:
    1. henry
    2. volt
    3. hertz
    4. coulomb
    ========= Answer is c =========
  7. One megahertz is equal to:
    1. 0.0001 Hz
    2. 100 kHz
    3. 1000 kHz
    4. 10 Hz
    ========= Answer is c =========
  8. One GHz is equal to:
    1. 1000 kHz
    2. 10 MHz
    3. 100 MHz
    4. 1000 MHz
    ========= Answer is d =========
  9. The 'rms value' of a sine-wave signal is:
    1. half the peak voltage
    2. 1.414 times the peak voltage
    3. the peak-to-peak voltage
    4. 0.707 times the peak voltage
    ========= Answer is d =========
  10. A sine-wave alternating current of 10 ampere peak has an rms value of:
    1. 5 amp
    2. 7.07 amp
    3. 14.14 amp
    4. 20 amp
    ========= Answer is b =========