Full Test 1 - EKT EEE - AFCAT MCQ

For x = 3, (x² – 8) > 0 so |x² - 8| = x² – 8

f(x) = x + (x² – 8)

f’(x) = 1 + 2x

f’(3) = 1 + 2(3) = 7

Conditional probability P(A/B): 

Angle between two vectors:

θ = 60°

Order of a differential equation is defined as the order of the highest order derivative and the degree of a differential equation, when it is a polynomial equation in derivatives, is defined as the highest power (positive integral index) of the highest order derivative.

The highest order derivative present in the given differential equation is  so it’s order is two. It is a polynomial equation in  the highest power raised to  is one, so its degree is one.

Doing row operation on the given matrix, we get

 

Since the number of non-zero rows is one,

∴ ρ(A) = 1

Lorentz force is the combination of electric force  and magnetic force  Thus the Lorentz force is given by  

Kinetic energyrepresents energy the mass possesses by virtue of its motion. Likewise, potential energy (PE=mgh) represents energy the mass possesses by virtue of its position.
E=KE+PE
E is the total energy of the mass: i.e., the sum of its kinetic and potential energies. It is clear that E is a conserved quantity: i.e., although the kinetic and potential energies of the mass vary as it falls, its total energy remains the same and one form of energy is being converted into other form of energy.

1 farad = 1 coulomb/volt
One farad is defined as the capacitance of a capacitor which requires a charge of one coulomb to establish a potential difference of one volt between its plates.

The process of electron emission from a metal surface by supplying thermal energy to it is known as thermionic emission.

The factors on which it depends are:

(i) the nature of the metal

(ii) the temperature of the surface of the metal.

The Magnetic field due to a long straight conductor is given as  where r is the distance from the conductor.

For a damped oscillation, we need a decaying exponential multiplied with a sinusoid. Only  y=ae^−αtcos(ωt+α)satisfies that criteria.

Astable Multivibrator shifts between two states thereby generating a square wave. In Bistable Multivibrator, a trigger pulse is needed for change from one stable state to another stable state (from 0 to 1 and 1 to 0) hence can be used to state binary data.

A working diode means the diode is biased or connected with the DC source. When a diode is forward biased (+ve terminal to anode and -ve terminal to cathode), it provides a low resistance path because it helps the majority carrier to crossover the barrier potential and conduct the flow of current. When a diode is reversed biased (-ve terminal to anode and +ve terminal to cathode) it provide a high resistance path because the majority carriers are flows away from the junction and no current conduction takes place.

The Frequency Response of an amplifier is presented in a form of a graph that shows output amplitude (or, more often, voltage gain) plotted versus frequency. Typical plot of the voltage gain of an amplifier versus frequency. The gain is null at zero frequency, then rises as frequency increases, level off for further increases in frequency, and then begins to drop again at high frequencies. The frequency response of an amplifier can be divided into three frequency regions.

The frequency response begins with the lower frequency region designated between 0 Hz and lower cut off frequency. At lower cutoff frequency f_L, the gain is equal to 0.707 A_mid. Amid is a constant midband gain obtained from the midband frequency region. The third, the upper frequency region covers frequency between upper cutoff frequency and above. Similarly, at upper cutoff frequency, f_H, the gain is equal to 0.707 A_mid. After the upper cutoff frequency, the gain decreases with frequency increases and dies off eventually.

Harmonic distortion in amplifiers is usually caused by the amplifier needing more voltage than its power supply can provide. It can also be caused by some part of the internal circuit (usually the output transistors) exceeding its output capacity

In positive feedback op-Amp acts in its saturation region

At the resonant frequency, the feedback factor (R2/R1) of a Wien bridge oscillator using Op-Amp, is 1/2. Hence, the amplifier gain must be greater than 2 to maintain sustained oscillations.

CMOS uses field effect transistors. It is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits.

FF is a hexadecimal number which has value 255 in decimal which is an odd number.

If G₀G₁G₂G₃ is a gray code number then the BCD equivalent number B₀B₁B₂B₃ can be estimated using:

B₃ = G₃

B₂ = B₃ ⊕ G₂

B₁ = B₂ ⊕ G₁

B₀ = B₁ ⊕ G₀

So, using the above rules, the BCD equivalent of gray code number 1001 is 1110

In binary multiplication, we only need to remember the following rules:

0 x 0 = 0

0 x 1 = 0

1 x 0 = 0

1 x 1 = 1

So, by using above rules when we will multiply binary 1000 with binary 1111 we will get binary 11110000 as the product.

In normal excitation, if load is increased the change in current is greater than the change in power factor and the power factor tends to become increasingly lagging.

In case of DC series motor, field generated depends on armature current. At no load, current drawn is very less hence the field generated is less. Since the back emf remains constant hence speed is inversely proportional to the flux. Thus the initial speed will get very high and the motor may get damaged at no load.

Transformer oil is a highly refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformers. Its function is to provide insulation and cooling.

Equalizer rings are used in lap wounded armatures only to remove any circulating currents in parallel paths.

A shunt reactor is connected in parallel with a transmission line or other load. They are used in transmission systems to counteract the effect of line parasitic capacitance. Thus they deal with the reactive component.

Self-bias are emitter biased circuit. Generates it's own DC bias voltage .For the emitter which has a considerable effect, on the base current .Any circuit which does generate such bias voltage without actually directly depending on an explicit power supply is a self-bias.

The mobility of electrons is more than that of holes because the probability of an electron having the energy required to move to an empty state in the conduction band is much greater than the probability of an electron having the energy required to move to the empty state in valance band. The mobility of hole is about half that of electrons.

Forbidden energy gap between valence band and conduction band is least in the case of impure silicon.