1. Tuned detectors are used in the frequency range of ________
a) 1 Hz to 100 Hz
b) 10 Hz to 100 Hz
c) 1 kHz to 100 kHz
d) 1 MHz to 100 MHz
Explanation: Tuned amplifier circuits are used as detectors in the low frequency range. Low frequency range usually ranges from 10 Hz to 100 Hz in AC bridges
2. Vibration galvanometers are used for ________
a) very high frequency
b) very low frequency
c) low audio frequency
d) high audio frequency
Explanation: Vibration galvanometers are used as detectors in AC bridges for low audio frequency. Low audio frequency ranges from 5 Hz to 1000 Hz
3. AC bridge is an outcome of ________
a) Kelvin bridge
b) Megger
c) De Sauty bridge
d) Wheatstone bridge
Explanation: Wheatstone bridge is the simplest form of bridge for the measurement of resistance and forms the basis for an AC bridge. Kelvin bridge is used for the measurement of low resistance and a megger is used for the measurement of high resistances.
4. At very low frequencies in a AC bridge, the source is _________
a) power line
b) e.m.f
c) galvanometer
d) tuned circuit
Explanation: Galvanometer is used for detecting the balance condition. The power line acts as a source of supply for bridge measurements in an AC bridge circuit at very low frequencies.
5. At high frequencies in an AC bridge, the source is _______
a) tuned amplifiers
b) oscillators
c) vibration galvanometer
d) high voltage source
Explanation: Tuned amplifiers are used as a source of voltage in AC bridges. Electronic oscillators are used as a source of supply for bridge measurements in an AC bridge circuit at high frequencies
6. The frequency range of a typical oscillator is _______
a) 1 Hz to 50 Hz
b) 1 kHz to 100 KHz
c) 40 Hz to 125 kHz
d) 1 MHz to 150 MHz
Explanation: An oscillator has a frequency range slightly above the audio frequency. A typical oscillator has a frequency range of 40 Hz to 125 kHz
7. The power output for a typical oscillator is _______
a) 1 kW
b) 1 MW
c) 1 mW
d) 7 W
Explanation: Oscillator usually has a low power output. A typical oscillator has a power output of around 7 W.
8. The output waveform in an oscillator is _______
a) sinusoidal
b) cosinusoidal
c) tangential
d) logarithmic
Explanation: AC supply is generally in the form of sinusoidal signal. In an electronic oscillator, output waveform is very close to sinusoidal
9. The output frequency of an oscillator is _______
a) unstable and fixed
b) stable and adjustable
c) stable and fixed
d) unstable and variable
Explanation: In an electronic oscillator, the output frequency is stable. It can be determined accurately and is also adjustable.
10. The output power of an oscillator is not enough to drive power circuits.
a) True
b) False
Explanation: Power circuits generally require a low output in order to function. An electronic oscillator provides sufficient output power to drive power circuits