Full Test 2 - EKT EEE - AFCAT MCQ

The determinant if matrix A is given as

|A|=−1

For x = r cos θ, y = r sin θ

We have x²+y²=r²

Order of the differential equation is the highest derivative in a differential equation. Hence the order is 2. 

We can write xⁿ=cosnθ+jsinnθ
The given equation can be written as 
=cosnθ+jsinnθ+cosnθ−jsinnθ
=2cosnθ

The power factor will be given as cosϕcos⁡ϕ. It can be calculated as ratio of resistance to impedance. Thus, .

Here C is the capacitance, Q is the charge and V is the voltage for a given capacitor. Their relation is being given as Q = CV.

Dimensions of force is MLT⁻². Energy = Force × Distance. Dimensions of energy are ML²T⁻². Power is energy per unit time. The dimensions of power are ML²T⁻³.

The speed of electromagnetic waves in free space is equal to the velocity of light.

A laser makes monochromatic light of a single, very precise frequency and colour. The laser line is also very coherent as the crest of every wave is lined up with the crest of other waves.

Orthographic projection, a common method of representing three-dimensional objects, usually by three two-dimensional drawings in each of which the object is viewed along parallel lines that are perpendicular to the plane of the drawing.

The given Op-Amp circuit uses positive feedback with input through inverting terminal it is a Schmitt trigger, since a Schmitt trigger circuit is also called a regenerative comparator circuit. The circuit is designed with a positive feedback and hence will have a regenerative action which will make the output switch levels.

It is basically an inverting comparator circuit with a positive feedback. The purpose of the Schmitt trigger is to convert any regular or irregular shaped input waveform into a square wave output voltage or pulse. Thus, it can also be called a squaring circuit.

Gain with feedback 

RC phase shift oscillator is used to invert the input for 180° phase difference. The single R-C network gives the 60° phase shift. Hence, we need three set of R-C network which have to be connected in cascade (series). The value of R and C can be chosen by the formula, 

Filter removes higher frequency component of rectified cutout signal therefore filter reduces ripple present in the signal and which gives smaller ripple factor.

When a positive voltage is applied to the N-type material and a negative voltage is applied to the P-type material, then a diode is connected in a reverse bias condition. In reserve bias the holes and electrons are attracted to the battery terminal and depletion region increased.

(10001101011001)₂=(0010−0011−0101−1001)₂=(2359)_H

Hexadecimal equivalent of binary number 10001101011001 is 2359

The half adder adds two single binary digits A and B. It has two outputs, sum (S) and carry (C). The carry signal represents an overflow into the next digit of a multi-digit addition. A half adder circuit is basically made up of an a AND gate with XOR gate.
Sum (S) = A⊕BA⊕B

Carry (C) = AB

NAND is a universal gate that means we can implement a whole logic whatever you can implement using AND, OR, Invert combination can be implement using NAND gates alone similarly NOR gates alone.

A NOR or an EX - NOR gate is one which gives the value one if and only if all operands have a value of zero and otherwise has a value of zero.

In an induction motor, the rotor copper losses are given as I²r₂, while the rotor input and rotor output are expressed as 

Transformer voltage comes into play in iron losses and the current is used to calculate copper losses. Thus the transformer ratings consist of both voltage and current and thus the ratings are expressed in KVA.

In under commutation, the commutation does not complete before the brush has moved from one commutator segment to the next. This leads to sparking at the trailing edge of the brush.

At cogging, the stator and rotor teeth get locked and rotor stops rotating after the locking.

The stator frame is the outermost part of the induction motor. It is made up of the cast iron and its main function is to provide mechanical support to the stator core. It is not designed to carry the stator flux.

Following are the 3 types of configuration:

• Common Base (CB) Configuration: no current gain but voltage gain
• Common Collector (CC) Configuration: current gain but no voltage gain
• Common Emitter (CE) Configuration: current gain and voltage gain

When we pop in a pentavalent element into the lattice. We have doped the silicon lattice with Phosphorous, a pentavalent element. Now pentavalent element has five electrons, so it shares a electron with each of the four neighbouring silicon atoms, hence four atoms are tied up with the silicon atoms in the lattice. This leaves an electron extra. This excess electron is free to move and is responsible conduction. Hence N-type (Negative Type) extrinsic semiconductor (silicon in this case) is made by doping the semiconductor with pentavalent element.

It is a majority carrier device. It is a semiconductor diode with a very fast switching action, but a low forward voltage drop. When a current flows through the diode there is a small voltage drop across the diode terminals. In a normal diode, the voltage drop is between 0.6 to 1.7 volts, while in a Schottky diode the voltage drop normally ranges between 0.15 and 0.45volts. This lower voltage drop provides higher switching speed and better system efficiency.

In Schottky diode, a semiconductor-metal junction is formed between a semiconductor and a metal, thus creating a Schottky barrier. The N-type semiconductor acts as a cathode and the metal side acts as the anode of the diode. The Schottky barrier diode is a unidirectional device conducting current flows only in one direction.

The Avalanche breakdown happens if the reverse bias voltage is very high, then the velocity and associated kinetic energy of carriers increases to a point that impact will cause ionization process  to a point where a high avalanche current is established.