A semiconductor differs from a conductor in that it has

Which of the following circuits is used for converting a sine wave into a square wave?

Which of the following elements of electrical engineering cannot be analyzed using Ohm’s law ?

Consider the following statements: A power supply uses bridge rectifier with a capacitor input filter. If one of the diodes is defective, then
1. The dc load voltage will be lower than its expected value
2. Ripple frequency will be lower than its expected value
3. The surge current will increase considerably
Which of the above statements are correct?

Three identical amplifiers each having a voltage gain of 50 are cascaded. The open loop voltage gain of the combined amplifier is

A clamper circuit
1. Adds or subtracts a dc voltage to or from a waveform
2. Does not change the shape of the waveform
Which of the above statements are correct? 

If a carrier of 100% modulated AM is suppressed before transmission, the power saving is nearly

When the modulating frequency is doubled the modulation index is halved and the modulating voltage remains constant. This happens when the modulating system is

The four basic elements in a PLL are loop filter, loop amplifier, VCO and

In a frequency modulated (FM) system, when the audio frequency is 500 Hz and audio frequency voltage is 2.4 V, the frequency deviation is 4.8 kHz. If the audio frequency voltage is now increased to 7.2 V then what is the new value of deviation?

In an IGBT cell the collector and emitter are respectively

The main units in a pulse code modulator are:
1. Sampler
2. Quantiser
3. Encoder
4. Comparator

NAND and NOR gates are called ‘Universal’ gates primarily because

To turn-off a GTO what is required at the gate?

In a power transformer, the core loss is 50 W at 40 Hz and 100 W at 60 Hz, under the condition of same maximum flux density in both cases. The core loss at 50 Hz will be

Consider the following advantages of a distributed winding in a rotating machine:
1. Better utilization of core as a number of evenly placed small slots are used
2. Improved waveform as harmonic emf’s are reduced
3. Diminished armature reaction and efficient cooling
Which of the above advantages are correct?

The breadth factor for 3rd harmonic emf of a 3-phase, 4-pole, synchronous machine having 36 stator slots is

Consider the following factors for a dc machine:
1. Interpole
2. Armature resistance
3. Reduction in field current
Which of the above factors are responsible for decrease in terminal voltage of a shunt generator?

A dc motor develops an electromagnetic torque of 150 N-m in a certain operating condition. From this operating condition, a 10% reduction in field flux and 50% increase in armature current is made. What will be new value of electromagnetic torque? 

If the capacitor of a capacitor-start single-phase motor fails to open when the motor picks up speed, 

If a square matrix of order 100 has exactly 15 distinct eigenvalues, then the degree of the minimum polynomial is 

For high speed reading and storing of information in a computer, the core shall be of 

Soft magnetic materials should have 

Orbital magnetic moment of an electron, in an atom, is of the order of 

When the temperature of a ferromagnetic material exceeds the Curie temperature, it behaves similar to a 

What is the correct sequence of the following materials in ascending order of their resistivity ?
1. Iron
2. Silver
3. Constantan
4. Mica
5. Aluminium
Select the correct answer using the codes given below : 

In the first Cauer network, with a pole at infinity, the first element must be

The total magnetic moment
1. is called saturation magnetization.
2. depends on the number of magnetic dipoles per unit volume, the instant electric current and the area of the current loop.
Which of the above statements is/are correct ? 

Susceptibility of a diamagnetic material is 1. Negative
2. Positive
3. Dependent on the temperature
4. Independent of the temperature 

Superconductivity is a material property associated with 

An atom in a crystal vibrates at a frequency, determined by
1. Crystal heat current
2. Crystal temperature
3. The stiffness of the bonds with neighbour atoms
Select the correct answer using the codes given below: 

Consider the following statements:
1. Nano means 10^–9 so that nano materials have an order of dimension higher than the size of atom and come in the form of rods, tubes, spheres or even thin sheets/films
2. Nano materials have enhanced of changed structural property
3. Nano elements lend themselves to mechanical processing like rolling, twisting, positioning
4. Nano elements show important electrical, magnetic and optical characteristics that are useful in electrical industry
Which of the above statements are correct? 

For a two-part reciprocal network, the three transmission parameters are A = 4, B = 7 and C = 5. What is the value of D? 

Consider the following as representations of reciprocity in terms of z-parameters:
1. z₁₁ = z₁₂                     2. z₁₂ = z₂₂
3. z₁₂ = z₂₁
Which of the above representations is/are correct? 

Kirchhoff’s current law is applicable to
1. Closed loops in a circuit
2. Junction in a circuit
3. Magnetic circuits
Which of the above is/are correct? 

Which of the following are satisfied in a non-linear network?
1. Associative               2. Superposition
3. Homogeneity             4. Bilaterality
Select the correct answer using the codes given below: 

Consider the following statements:
1. Network theorems are not derivable from Kirchhoff’s law
2. To get the Norton current, one has to short the current source
3. Thevenin’s theorem is suitable for a circuit involving voltage sources and series connections
Which of the above statements is/are correct? 

What is the octal equivalent of (5621.125)10? 

What is the hexadecimal representation of (657)₈? 

In potential transformers, the secondary turns are increased slightly and the primary and secondary windings are wound as closely as possible to compensate for 

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

For the intrinsic gallium-arsenide, the conductivity at room temperature 25°C is 10^-6 (ohm-m)^-1, the electron and hole nobilities are 0.85 m²/V-s and 0.04 m²/V-s respectively. What is the intrinsic carrier concentration at the room temperature?

The resistivity of intrinsic germanium at 30°C is 0.46 –m. What is the intrinsic carrier density at 30°C if the electron mobility is 0.38 m²/V-s and the hole mobility is 0.18 m²/V-s?

Heat conduction in a semiconductor takes place

Brewster angle is the angle when a wave is incident on the surface of a perfect dielectric at which there is no reflected wave and the incident wave is

An electrical breakdown of a p-n junction occurs if

The chief deterrent to the widespread application of superconducting materials is

Which one of the following properties is not observed in the carbon nanotubes ?

The evidence for the importance of electron-phonon interaction in super-conductors comes from

Which one of the following materials is used for cable insulation ?