RRB JE Electrical (CBT II) Mock Test- 7 - Electrical Engineering (EE) MCQ

Radiation is the transfer of heat energy through space by electromagnetic radiation.

- Maximum allowable Earth resistance for

Major power station = 0.5 Ohm, is the accepted norm.

The instantaneous voltage across the inductor is expressed as the product of inductance and a rate of change of current through it as it doesn't allow any certain change of current through it.
V_l = L × (di/dt)

VIRUS stands for 'Vital Information Resource Under Seige'. It is a segment of self-replicating code planted illegally in a computer program, often to damage or shut down a system or network.

Ferrite core is a type of magnetic core made of ferrite on which the windings of electric transformers and other wound components such as inductors are formed.

It is used for its properties of high magnetic permeability coupled with low electrical conductivity (high resistance)

It helps in preventing eddy currents

The μ_r value of a ferromagnetic material depends upon temperature, μ_r  decreases with increase in temperature and at critical temperature ‘curie temperature’ the ferromagnetic material becomes paramagnetic. The curie temperature of iron is 770 degree Celsius.

Let the resistance of each resistor = R Ω
If three equal resistors are connected in series (R₁) = 3R
Power dissipated in this case (P₁) = 10 W
If three equal resistors are connected in parallel (R₂) = R/3
Power dissipated in this case = P₂
We know that, P = V²/R
For the same voltage, power is inversely proportional to resistance.
From the first case to the second case, the resistance decreases by 9 times. Hence the power will increase by 9 times.
Power in the second case (P₂) = 90 W

A pressure transducer is used to convert a certain value of pressure into its corresponding mechanical or electrical output.

The transducers used for static pressure measurement are

According to Faraday's law, the current flowing through a coil produces the magnetic field. Hence the source of a magnetic field is the current loop.

Hydrogen and Sulphur are already balanced

Start with the balancing of oxygen

Oxygen on RHS = 3

Oxygen on LHS = 2

H₂S+3/2O₂→H₂O+SO₂

To get an integer number of moles, multiply the equation by 2

2H₂S+3O₂→2H₂O+2SO₂

The potential difference is defined as work done per unit charge.

This implied that, V = W/q

Where V is Potential Difference; W is Work Done; q is charge

Or, W= V× q

= 2×10

= 20 Joules.

1) Resistance is proportional to length: When wire length becomes half, the resistance becomes half

2) Resistance is inversely proportional to the cross-sectional area: Diameter, becomes half, area reduces by the square of diameter i.e. 1/4 times; Therefore, resistance becomes 4 times more

Rutherford designed an experiment in which fast-moving alpha (α)-particles were made to fall on a thin gold foil.

Rutherford’s prediction

Rutherford’s Observation

Observations and Conclusions:
Observation 1 :
Most alpha particles passed through the gold foil undeflected.
Conclusion 1:
Atom consists of mostly empty space
Observation 2.
Some alpha particles bounced off from the nucleus, while others were deflected through large and small angles
Conclusion 2 :
Atom consists of a dense center, called nucleus
Observation 3:
No alpha particle was sucked into the nucleus
Conclusion 3:
Using the fact that Alpha particles carry a positive charge, and like charges repel, while unlike charges attract he concluded atom consists of a positively charge nucleus

Current (I) = 2 A
Flux (ϕ) = 8 × 10^-5 weber
Number of turns (N) = 25
Mutual inductance = NØ/I = 25 x 8 x 10 ^-5/2 = 1 mH

The atmosphere is a thin layer of gases which stays above the earth due to the force of gravitation. Its air is colourless, odourless and tasteless.
Nitrogen and oxygen are two major gases of the atmosphere. Carbon dioxide (CO2), Helium, Ozone, Argon and hydrogen are found in lesser quantities. Apart from these gases, tiny dust particles are also present in the air.
The atmospheric composition of gases are as follow

A fuse is an electrical safety device that operates to provide over current protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby interrupting the current.

Magnetic Units:

The values of maximum flux density for different transformers are as follows:

For hot rolled silicon steel:

For CRGO core:

Concept:

Decomposition Reaction:

A single reactant breaks down to give simpler products. This type of reaction is called as decomposition reaction

Application:

When silver chloride is exposed to sunlight, white silver chloride turns grey in sunlight.

This is due to the decomposition of silver chloride into silver and chlorine by light

Underlying Reaction:

Resistance switching:

Approximate quantities of different gases in the atmosphere in PPM are given below.

Given that, emf (V) = 16 V
di/dt = ^_4-(-4)/0.1 = 80
We know that, V _L = 
⇒ L = 16/80 = 0.2 H

Capacitor start induction motors are used in refrigerators. The other applications of capacitor start induction motor are: