Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Inductance Comparison Bridge”.

1. Inductance comparison bridge is used to compute _________

a) unknown inductance and resistance

b) unknown resistance

c) unknown inductance

d) unknown capacitance

Answer: a

Clarification: By making use of an inductance comparison bridge, the values of unknown inductance and its internal resistance can be determined.

2. Ratio arms of the bridge consists of _________

a) pure inductances

b) pure resistances

c) pure capacitances

d) inductance and capacitance

Answer: b

Clarification: An inductance comparison bridge is basically used to compute the unknown resistance and inductance values. Ratio arms of an inductance bridge consists of pure resistances.

3. Value of unknown resistance is found by using which of the following relation?

a) R_{x} = (frac{R_1 R_3}{R_2})

b) R_{x} = (frac{R_2 R_1}{R_3})

c) R_{x} = (frac{R_2 R_3}{R_1})

d) R_{x} = (frac{R_2}{R_1})

Answer: c

Clarification: The inductance comparison bridge mainly consists of pure resistances in its ratio arm. The value of unknown resistance is given by the relation R_{x} = (frac{R_2 R_3}{R_1}).

4. The value of unknown inductance is found by using which of the following relation?

a) L_{x} = (frac{R_1 L_3}{R_2})

b) L_{x} = (frac{R_2}{R_1})

c) L_{x} = (frac{L_3}{R_1})

d) L_{x} = (frac{R_2 L_3}{R_1})

Answer: d

Clarification: At balance condition in an inductance comparison bridge, the value of unknown inductance is found by using the relation L_{x} = (frac{R_2 L_3}{R_1}).

5. Inductance control is obtained by _________

a) using R_{2}

b) using R_{1}

c) using R_{3}

d) using L_{x}

Answer: a

Clarification: In an inductance comparison bridge, the resistance R_{2} and R_{3} are variable. The value of resistance R_{2} is varied so as to control the inductance of the bridge.

6. Bridge depends on frequency.

a) True

b) False

Answer: b

Clarification: In an inductance comparison bridge, the balance equation is independent of frequency. As a result the bridge balance condition remains unaffected by variation in the value of frequency.

7. Bridge can be used at audio frequency.

a) True

b) False

Answer: a

Clarification: An inductance comparison bridge can be used for measurement of unknown inductance at a wide range of audio frequencies in the order of a few Hz to KHz.

8. Bridge is used for the measurement of _________

a) high Q factor

b) medium Q factor

c) low Q factor

d) very low Q factor

Answer: b

Clarification: The inductance comparison bridge is used for the measurement of low Q factor values of the order of 1 to 10. It cannot be used for the measurement of Q factors below 1. As a result, the bridge is used for the measurement of medium Q factor values.

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