National Champion Test -GATE 2018 EE: Electrical Measurement & Measuring Instrument for ESE & GATE EE Exams

Question 1

In wheat stone bridge, the error occurs due to nonlinearity, is ordinarily small, and can be ignored when measuring:

Question 2

The ac bridge shown in the figure is used to measure the impedance Z.

If the bridge is balanced for oscillator frequency f = 2 kHz, then the impedance Z will be

Question 3

Resistance R₁ and R₂ have, respectively, nominal values of 10Ω and 5Ω and tolerances of ±5% and ±10%. The range of values for the parallel combination of R₁ and R₂ is

Question 4

In an oscilloscope, which among the following option shows sequential sampling?

Question 5

The items in Group I represent the various types of measurements to be made with a reasonable accuracy using a suitable bridge. The items in Group II represent the various bridges available for this purpose. Select the correct choice of the item in Group II for the corresponding item in Group I from the following

Question 6

A 500 A/5 A, 50 Hz current transformer has a bar primary. The secondary burden is a pure resistance of 1 Ω and it draws a current of 5 A. If the magnetic core requires 250 AT for magnetization, the percentage ratio error is

Question 7

An incandescent lamp is marked 40 W, 240V. If resistance at room temperature (26 °C) is 120Ω, and temperature coefficient of resistance is 4.5 × 10^–3/ °C, then its 'ON' state filament temperature in °C is approximately_____

Question 8

The inductance of a certain moving–iron ammeter is expressed as L = (10 + 3θ - θ²/4) μH, where θ is the deflection in radians from the zero position. The control spring torque constant is 25 × 10^–6 Nm/radian. The deflection of the pointer in radian when the meter carries a current of 5A is

Question 9

A basic D' Arsonval movement with a full scale deflection of 50 μA and internal resistance of 500 Ω is used as voltmeter. The value of the multiplier resistance needed to employ this meter to measure a voltage range of (0 - 10) V is given by

Question 10

An analog voltmeter uses external multiplier settings, with a multiplier setting of 20 kΩ, it reads 440 V and with a multiplier setting of 80 kΩ , it reads 352 V. For a multiplier setting of 40 kΩ, the voltmeter reads ?

Question 11

A 4 ½ digit DMM has the error specification as: 0.2% of reading +10 counts. If a dc voltage of 100 V is read on its 200 V full scale, the maximum error that can be expected in the reading is

Question 12

The time.div and voltage/div axes of an oscilloscope have been erased. As student connects a 1 kHz, 5V p-p square wave calibration pulse to channel 1 of the scope and observes the screen to be as shown in upper trace of the figure. An unknown signal is connected to channel 2 (lower trace) of the scope. If the time, the amplitude (p–p) and period of the unkmown signal are respectively

Question 13

A wattmeter reads 400 W when its current coil is connected in the R phase and its pressure coil is connected between this phase and the neutral of a symmetrical 3–phase system supplying a balanced star connected 0.8 p.f. inductive load. The phase sequence is RYB. What will be the reading of this wattmeter if its pressure coil alone is reconnected between the B and Y phases, all other connections remaining as before?

Question 14

The simplified block diagram of a 10–bit A/D converter of dual slope integrator type is shown in Figure. The 10–bit counter at the output is clocked by a 1 MHz clock. Assuming negligible timing overhead for the control logic, the maximum frequency of the analog signal that can be converted using this A/D converter is approximately

Question 15

An electro dynamometer wattmeter measures power in 1 - ∅ circuit. Load voltage 230 V and current 5 A at lagging pf of 0.1, wattmeter potential coil circuit resistance is 10 kΩ and inductance is 100 mH then ___________% error will be the error.

Question 16

The arms of an ac bridge shown in figure below are arranged, for balance as follows:

and

The supply frequency is 450 Hz. Determine the loss angle of condenser.

Question 17

A strain gauge forms one arm of the bridge shown in the figure below and has a nominal resistance without any load as Rs = 300Ω. Other bridge resistances are R₁ = R₂ = R₃ = 300Ω. The maximum permissible current through the strain gauge is 20 mA. During certain measurement when the bridge is excited by maximum permissible voltage and the strain gauge resistance is increased by 1% over the nominal value, the output voltage V0 in mV is

Question 18

Consider the following types of damping:
1) Air-friction damping
2)Fluid-friction damping
3)Eddy-current damping
PMMC type instruments use which of the above?