Questions and answers for exam Preparation

MCQs

Total Questions : 152 | Page 12 of 16 pages

Question 111. Q Meter is used to measure _________

Q factor of an inductive coil
Only the effective resistance
Only bandwidth
Q factor of an inductive coil, the effective resistance, and bandwidth

Discuss Question

Answer: Option D. -> Q factor of an inductive coil, the effective resistance, and bandwidth
Answer: (d).Q factor of an inductive coil, the effective resistance, and bandwidth

Question 112. A circuit tuned to a frequency of 1.5 MHz and having an effective capacitance of 150 pF. In this circuit, the current falls to 70.7 % of its resonant value. The deviates from the resonant frequency are 5 kHz. Effective resistance of the circuit is?

2 Ω
3 Ω
5.5 Ω
4.7 Ω

Discuss Question

Answer: Option D. -> 4.7 Ω
Answer: (d).4.7 Ω

Question 113. Consider a circuit consisting of two capacitors C₁ and C₂. Let R be the resistance and L be the inductance which are connected in series. Let Q₁ and Q₂ be the quality factor for the two capacitors. While measuring the Q value by the Series Connection method, the value of the Q factor is?

Q = \(\frac{(C_1 – C_2 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Q = \( \frac{(C_2 – C_1 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Q = \( \frac{(C_1 – C_2 ) Q_1 Q_2}{Q_2 C_2 – Q_1 C_1}\)
Q = \( \frac{(C_2 – C_1 ) C_1 C_2}{Q_1 C_1 – Q_2 C_2}\)

Discuss Question

Answer: Option A. -> Q = \(\frac{(C_1 – C_2 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Answer: (a).Q = \(\frac{(C_1 – C_2 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)

Question 114. Q factor of a coil measured by the Q Meter is _________ the actual Q of the coil.

Equal to
Same but somewhat lesser than
Same but somewhat higher than
Not equal to

Discuss Question

Answer: Option B. -> Same but somewhat lesser than
Answer: (b).Same but somewhat lesser than

Question 115. Consider a circuit consisting of two capacitors C₁ and C₂. Let R be the resistance and L be the inductance which are connected in series. Let Q₁ and Q₂ be the quality factor for the two capacitors. While measuring the Q value by the Parallel Connection method, the value of the Q factor is?

Q = \(\frac{(C_1 – C_2 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Q = \(\frac{(C_2 – C_1 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Q = \(\frac{(C_1 – C_2 ) Q_1 Q_2}{Q_2 C_2 – Q_1 C_1}\)
Q = \(\frac{(C_2 – C_1 ) C_1 C_2}{Q_1 C_1 – Q_2 C_2}\)

Discuss Question

Answer: Option B. -> Q = \(\frac{(C_2 – C_1 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)
Answer: (b).Q = \(\frac{(C_2 – C_1 ) Q_1 Q_2}{Q_1 C_1 – Q_2 C_2}\)

Question 116. Consider the following statements regarding the sources of error in a Q Meter.
i) If a coil with a resistance R is connected in the direct measurement mode and
If the residual resistance of the Q Meter is 0.1 R,
Then the measured Q of the coil would be 1.1 times the actual Q.
ii) If the inductance to be measured is less than 0.1 μH.
The error due to the presence of residual inductance cannot be neglected.
iii) The presence of a distributed capacitance modifies the effective Q of the coil.
Which of the above statements are correct?