NTPC Instrumentation Engg Question Paper

NTPC Instrumentation Questions and Answers with explanation, NTPC Previous Question Papers, NTPC Sample Placement Papers, NTPC Technical Questions and Answers

Technical Questions

1.psychrometric chart is used to determine

(A) pH
(B) Sound velocity in glasses
(C) 2 CO concentration
(D) Relative humidity

2.A n LED emitting at 1 µm with a spectral width of 50 nm is used in a Michelson interferometer. To obtain a sustained interference, the maximum optical path difference between the two arms of the interferometer is

(A) 200 µm
(B) 20 µm
(C) 1 µm
(D) 50 nm

3. T he bridge method commonly used for finding mutual inductance is

(A) Heaviside Campbell bridge
(B) Schering bridge
(C) De Sauty bridge
(D) Wien bridge

4. A periodic voltage waveform observed on an oscilloscope across a load is shown. A permanent magnet moving coil (PMMC) meter connected across the same load reads

(A) 4 V
(B) 5 V
(C) 8 V
(D) 10 V

5. Assuming both the voltage sources are in phase, the value of R for which maximum power is transferred from circuit A to circuit B is

(A) 0.8Ω
(B) 1.4 Ω
(C) 2 Ω
(D) 2.8 Ω

6.A double convex lens is used to couple a laser beam of diameter 5 mm into an optical fiber with a numerical aperture of 0.5. The minimum focal length of the lens that should be used in order to focus the entire beam into the fiber is

(A) 1.44 mm
(B) 2.50 mm
(C) 4.33 mm
(D) 5.00 mm

7.An analog voltmeter uses external multiplier settings. With a multiplier setting of 20 k Ω it reads 440 V and with a multiplier setting of 80 k Ω it reads 352 V. For a multiplier setting of 40 k Ω the voltmeter reads

(A) 371 V
(B) 383 V
(C) 394 V
(D) 406 V

8.In the following figure, C1 and C2 are ideal capacitors. C1 has been charged to 12 V before the ideal switch S is closed at t = 0. The current i(t) for all t is

(A) zero
(B) a step function
(C) an exponentially decaying function
(D) an impulse function

9.T he output Y of a 2-bit comparator is logic 1 whenever the 2-bit input A is greater than the 2-bit input B. The number of combinations for which the output is logic 1, is

(A) 4
(B) 6
(C) 8
(D) 10

10.Consider the given circuit.

In this circuit, the race around

(A) does not occur
(B) occurs when CLK = 0
(C) occurs when CLK = 1 and A = B = 1
(D) occurs when CLK = 1 and A = B = 0