UPSC ESE Electrical Engineering Solved Papers

What is the power supplied by each element in the circuit shown below?

What are $V_0$ and i respectively in the circuit shown below?

The electron beam in a TV picture tube carries $10^{15}$ electrons per second. What is the voltage $V_0$ needed to accelerate the electron beam to achieve 4 W?

Consider the following statements regarding network theorems:

1. With independent sources, superposition theorem can be used only when the control functions are external to the network containing the sources, so that the controls are unchanged as the sources act one at a time.
2. A linear, active, resistive network, which contains one or more voltage or current sources, can be replaced by a single voltage source and a series resistance or by a single current source and a parallel resistance. The voltage is called the Thévenin equivalent voltage and the current is Norton current.
3. The two resistances are the same in both Thévenin's and Norton's theorems which are obtained by deactivating all the sources.

Which of the above statements is/are correct?

A 10-ohm resistor has a current of $i = 2.5\sin\omega t\text{ (A)}$. What are the values of voltage and power respectively over one cycle of $\omega = 500\text{ rad/s}$?

For the network given below, what are the Norton's current and Thévenin's voltage at the terminals a and b?

Consider the following statements regarding power measurement by two-wattmeter method:

1. Two wattmeters connected in any two lines of a three-phase, three-wire system will correctly indicate the total three-phase power by the sum of the two meter readings.
2. A meter will attempt to go downscale if the phase angle between the voltage and current exceeds 180°.
3. In practical case, the balanced load is usually known to be inductive ($\theta > 0^\circ$).

Which of the above statements is/are correct?

What are the Z-parameters for the network given below?

The simplified model of a bipolar junction transistor for small signals is shown in the figure below:

What are the h-parameters?

Which one of the following statements is not correct regarding mutual inductance and transformers?

Consider the following statements regarding factors affecting the capacitance:

1. The area of the plates is directly proportional to the charge; the larger the plate area, the more electric charges that can be stored.
2. The longer the distance between the two plates, the stronger the produced electric field that will increase the ability to store charges. Therefore, the distance between the two plates is directly proportional to the capacitance.
3. Different insulating materials will have different impacts on the capacitance. The dielectric constant is directly proportional to the capacitance.

Which of the above statements is/are correct?

Which of the following is/are not discharging equation/equations for an R-C circuit?

1. Capacitor voltage $v_C = V_0 e^{-\frac{t}{RC}}$
2. Resistor voltage $v_R = E e^{-\frac{t}{RC}}$
3. Discharging current $i = \frac{V_0}{R} e^{-\frac{t}{RC}}$

Select the correct answer using the code given below.

Match the following Lists regarding time constant with capacitor discharging voltage:

Select the correct answer using the code given below:

A single-range laboratory-type potentiometer has an 18-step dial switch where each step represents 0.1 V. The dial resistors are $10\,\Omega$ each. The slide wire of the potentiometer is circular and has 11 turns and a resistance of $12\,\Omega$ per turn. The slide wire has 100 divisions and interpolation can be done to one-fourth of a division. What is the measuring range of the potentiometer?

Consider the following statements regarding Maxwell's bridge:

1. Maxwell's bridge is limited to measurement of low inductors.
2. The final balance equations of Maxwell's bridge are dependent of frequency.
3. The balance equation of Maxwell's bridge is dependent of losses associated with the inductor.

Which of the above statements is/are correct?

Match the following Lists:

Select the correct answer using the code given below:

The coil of a moving-coil voltmeter is 40 mm long and 30 mm wide, and has 100 turns on it. The control spring exerts a torque of $240\times 10^{-6}\text{ N-m}$ when the deflection is 100 divisions on full scale. If the flux density of the magnetic field in the air gap is $1\text{ Wb/m}^2$, what is the resistance that must be put in series with the coil to give one volt per division? (The resistance of the voltmeter coil may be neglected)

Consider the following statements regarding moving-iron instruments:

1. Moving-iron instruments have their deflection proportional to the square of the current flowing through the coil.
2. Moving-iron instruments have uniform scale marking.
3. Whatever be the polarity of the current in the coil, the deflection of a moving-iron instrument is in the same direction.

Which of the above statements is/are correct?

What is the equation for deflection of the pointer in an electrodynamometer-type instrument when it is operated with AC?

Consider the following statements regarding induction-type instruments:

1. If $\alpha = 0$, i.e., if two fluxes are in phase, then the net torque is maximum. If, on the other hand, $\alpha = 90^\circ$, the net torque is maximum for given values of $\phi_{1m}$ and $\phi_{2m}$.
2. The net torque is in such a direction as to rotate the disc from the pole with lagging flux towards the pole with leading flux.
3. The expression for torque has a steady value at all times.

Which of the above statements is/are correct?

An electrodynamometer-type wattmeter has a current coil with a resistance of $0.1\,\Omega$ and a pressure coil with resistance of $6.5\,\Omega$. What is the percentage error while the meter is connected as current coil to the load side, if the load is specified as 12 A at 250 V with unity power factor?

What is the expression for deflecting torque in single-phase induction-type energy meter?

When secondary winding of current transformer is open circuited with primary winding still energized, the large flux greatly increases the

The purpose of the start bit in digital voltmeter is to

In general, the range of digital multimeter display is