An inductance of one H carrying a current of two amperes will store the energy of
ISRO Scientist or Engineer Electrical 2017
For the following questions answer them individually
The square waveform of current has following relation between r.m.s value and average value
Two numbers of 500 ohms one watt resistors are connected in parallel. Their combined resistance and wattage rating will be
In a long uniform coil of inductance 2L and associated resistance 2R ohms is physically cut in to two exact halves which are rewound in parallel. The resistance and inductance of the combination are
For transfer function of a physical two-port network
The starting torque of a three phase induction motor can be increased by
The capacitor start-capacitor run single phase induction motor is operationally a
What would happen if the field of a D.C. shunt motor is opened?
Equalizer rings in D.C. generator with lap windings are used for
The Buchholz relay is normally used to protect the
The power transformer is a
A change of 5% in supply voltage to an induction motor will produce a change of approximately
If the supply frequency to the transformer is increased, the iron loss
The maximum temperature permitted for class A insulation is
Two transformers connected in parallel share load in the ratio of their KVA ratings, provided their ohmic impedance are
The high frequency hum in the transformers is mainly due to
A 400/200 volts transformer has pu impedance of 0.05. The HV side voltage required to circulate full load current during short circuit test is
Non-loading heat run test on transformers is performed by means of
A three phase induction motor is driving full-load torque which is independent of speed. If the line voltage drops to 90% of the rated value, % increase in motor copper losses
A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed
The steam input in to a turbogenerator connected to infinite bus is increased. Which of the events will take place?
In an ideal transformer, which of the following statement is correct?
The voltage applied to a transformer primary is increased keeping v/f fixed. How will core loss and magnetizing current change?
Frequencies in the UHF range normally propagate by means of
Indicate the antenna that is not wideband
The depth of penetration of a wave in a lossy dielectric increases with increasing
Copper behaves as a
Assuming constant transmission efficiency, if voltage is increased ‘n’ times, the size of the conductor would be
Shunt conductance in overhead power transmission lines is primarily due to
The dielectric strength of SF6 gas (used in circuit breakers) is approximately
Ferranti effect states that under certain conditions, the sending end voltage is
The equal area criterion of stability is applicable to
The power transmission capacity of the transmission line is
If the torque angle ‘delta’ increases indefinitely, the system indicates
Resistance switching is normally employed in
Series capacitors are used to
Over fluxing protection is normally recommended for
In general AC distribution systems, arc interruption in vacuum circuit breakers are designed to function in a time period of
Systems for Protection from negative sequence current is provided normally for
Bundled conductors are mainly used in high voltage overhead transmission lines to
Surge impedance of overhead transmission line is normally in the order of
The bode diagram approach is applied to
Which of the following methods is the strongest tool to determine the stability and the transient response of the system?
If the gain of a critically damped system is increased, it will become
The frequency domain and time domain are related through
A system with characteristic equation $$s^2 + 2 s^3 + 11 s^2 + 18 s + 18 = 0$$ will have closed loop poles such that
If the gain of an open loop system is doubled, the gain margin
An all pass network imparts only
An ON-OFF controller is
The transfer function of a phase lead controller is $$(1 + 3Ts) / (1 + Ts)$$. The maximum value of phase provided by this controller is
The thermal time constant is the time
Which of the following circuit will have no transients?
A conductor of length 100 cm moves right angles to a magnetic field of flux density of 2 wb/sq.m. with the velocity of 25 m/second. The induced emf in the conductor will be
Which of the following devices are required to measure three phase balanced power?
The sensitivity of an instrument is
Potentiometer sensitivity can be increased by
Low resistance is measured with
Which bridge is used to determine frequency?
The core of a moving iron instrument is made up of permalloy to
Accuracy is defined as
If three amplifiers having the same bandwidth are cascaded, the bandwidth of the resulting amplifier will be
An element is said to have negative resistance when
The operational amplifiers are seldom used for differentiation because
Which of the following multivibrator is called the flip flop?
The amount of feedback applied to an amplifier reduces the gain by a factor of 10. The bandwidth
In a negative feedback amplifier, the output impedance is decreased
The ROM consists of
An ideal rectifier should have transformer utilization factor (TUF) of 1. If the actual TUF is 3.5, it shows that
A power MOSFET is a
When transistors are used in series or parallel, a snubber circuit is used to
$$\lim_{x \rightarrow \infty}\left(\frac{x + \sin x}{x}\right)$$ is equal to
A fair (unbiased) coin was tossed four times in succession and resulted in the following outcomes: (i) Head (ii) Head (iii) Head (iv) Head. The probability of getting a ‘Tail’
when the coin is tossed again is
What are the eigen values of the following $$2 \times 2$$ matrix $$\begin{bmatrix}2 & -1 \\-4 & 5 \end{bmatrix}$$ ?
$$\int_{0}^{\frac{\pi}{2}} \int_{0}^{\frac{\pi}{2}} \sin (x + y)dx dy $$ is
In the Taylor series expansion of $$e^x + \sin x$$ about the point $$x = \pi$$ , the coefficient
A deck of five cards (each carrying a distinct number from 1 to 5) is shuffled thoroughly. Two cards are then removed from the deck, one at a time. What is the probability that the two cards are selected with the number of the first card being one higher than the number on the second card?
Using trapezoidal rule for the table given below $$\int_{4}^{5.2} \ln x dx$$ will be
Find the z transform of $$(n + 1)^2$$
Consider the following system of equations in three real variables $$x_1, x_2$$ and $$x_3$$
$$2x_1 - x_2 + 3x_3 = 1$$
$$3x_1 - 2x_2 + 5x_3 = 2$$
$$-x_1 - 4x_2 + x_3 = 3$$
The system of equations has :
Which of the following functions would have only odd powers of x in its Taylor series expansion about the point x = 0?
