RRB JE ECE (CBT II) Mock Test- 1 - Electronics and Communication Engineering (ECE) MCQ

The internet connects to different systems on the network and allows the users to send Emails, browse websites and share information on the server.

D in DRAM stands for Dynamic, which means there is leakage of charge where periodic refreshing is required.

​CTRL + D closes the command line shell. This sends an EOF (End of file) marker to shell, and shell exits when it receives this marker. This is similar to running the exit command.

We know, μ = tan i_p

Where i_p = Polarization or Brewster’s angl

∴ ip = tan^-1 μ = tan-1(1.732) = 60°

• Gujarati poet Sitanshu Yashashchandra was awarded 'Saraswati Samman 2017' on 22 January 2019.
• He was awarded for his poetry collection in Gujarati named 'Vakhar'.
• The award was instituted by K.K.Birla foundation.
• The award is given every year to an outstanding work of an Indian citizen published during the last 10 years in any of the languages mentioned in Schedule 8 of the constitution.

A local area network (LAN) is a computer network tht interconnects computers within a limited area such as a residence, school, laboratory, university campus etc.

LANs can span over a limited range i.e. of 1 km in radius.

WLAN, which stands for 'Wireless Local Area Network', is when a mobile user connects to a local area network via a wireless connection.

Control Bus is a group of conducting wires, which is used to generate timing and control signals to control the associated peripherals, the microprocessor uses control bus to process data.

Some control signals are:

Memory read

Memory write

I/O read

I/O Write

Opcode fetch

A queue is an ordered list in which insertions are done at one end (rear) and deletions are done at other ends (front). The first element to be inserted is the first one to be deleted. Hence, it is called First in First out (FIFO) or Last in Last out (LILO) list.

Permeability is the measure of the degree to which a material can be magnetized

B = μ H

μ = B/H
Hence, the correct option is (C)

In the cast resin-based cable joints, the polyurethane based casting resins provide:

1. Mechanical protection
2. Electrical insulation
3. Moisture imperviousness to the joint

Cast resin-based joints are used to make straight joints.

Straight joints can be used for indoor, outdoor, submerged and underground cable jointing.

Norton current is nothing but the short circuit current across the load terminal AB.
By applying superposition theorem
When only voltage source active and another source are inactive

I ₁ = 30/15 = 2 A
Now consider 10 A current source

I₂ = 10 A
Now consider 5 A current source

I₃ = 5 A
Norton current I_N = I₁ + I₂ + I₃ = 2 + 10 + 5 = 17 A

In a parallel interface, there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously, just as all of the bits of a word are transferred simultaneously over the data bus.

Concept:

The conductivity of a semiconductor depends on two factors 

1. Carrier concentration (electrons in Conduction band and Holes in Valence band)

2. Mobility

Application:

At zero kelvin the thermal energy is zero.

The energy is not sufficient to excite electrons from conduction band to valence band, hence there are no free charge carriers at 0K

Thus an instrinsic semicondcutor behaves as insulator at OK.

• Delhi is the only union territory of India which has its own High court.
• It was established on 31 October 1966.
• The High Court of Delhi was established with Chief Justice KS Hegde, Justice ID Dua, Justice HR Khanna and Justice SK Kapur as the 4 judges.
• Chandigarh comes under the jurisdiction of Punjab and Haryana High Court.
• Puducherry comes under the jurisdiction of Madras High Court.
• Daman and Diu come under the jurisdiction of Bombay High Court.

Concept:

Dielectric Strength:

The maximum electric field that the material can withstand under ideal conditions without breaking down (i.e. without failure of its insulating properties).

Dielectric Loss:

Dielectric loss, loss of energy that goes into heating a dielectric material in a varying electric field.

For example, a capacitor incorporated in an alternating-current circuit is alternately charged and discharged each half cycle.

During the alternation of polarity of the plates, the charges must be displaced through the dielectric first in one direction and then in the other and overcoming the opposition that they encounter leads to a production of heat through dielectric loss.

Application:

To withstand high electric field the dielectric strength of an insulator should be high.

To minimize losses, the dielectric losses should be low.

As the temperature increases, the number of electrons gain energy and jump from either donor states or valence band into conduction band.
When electrons jump into conduction band from valence band, it leaves a vacancy called hole behind.
Thus With increase in temperature both, electron and hole concentration increases in n-type semiconductor and the overall semiconductor remains neutral all time.

Concept:

Substances whose odour changes in acidic or basic media. These are called olfactory indicators.

Example:

The effect of Negative feedback in op amp are:​
1. Reduction in Noise
N of = N₀ / 1 + Aβ
N₀ = Noise without feedback
N_of = Noise with feedback
2. Decrease in Lower Cut off frequency
f if = f _l / 1 + Aβ
f_lf = lower 3 dB frequency with feedback
f_l = lower 3 dB frequency without feedback
3. Upper cut off frequency
f _hf = f _h(1 + Aβ)
f_hf = upper 3 dB frequency with feedback
f_h = upper 3 dB frequency without feedback
Since the lower cutoff frequency decreases and upper cutoff frequency increases, an op amp with negative feedback has more bandwidth.

Return:

Return statement can be used to come out of the recursion

int sum(int num)

{

 if (num! = 0)

 return num + sum(num-1); // sum() function calls itself

 else

 return num;

}

Here when num becomes 0, return num statement is used to terminate the recursion.

Break statement:

Break statement is used to terminate the loop

Exit:

Exit is used to terminate the whole program

• Jordan has unveiled its first underwater military museum off the coast of Aqaba.
• The vehicles, including tanks, troop carriers and a helicopter, imitating a battle formation, have been stationed at a coral reef in the Red Sea.
• Aqaba is the lone port city of Jordan and is a popular destination for divers.

Concept:

Matthiessen’s rule:

An empirical rule which states that the total resistivity of a crystalline metallic specimen is the sum of the resistivity due to thermal agitation of the metal ions of the lattice and the resistivity due to the presence of imperfections in the crystal.

The crystal Imperfections include:

• Atoms displaced by lattice vibrations
• Vacancies and interstitials
• Dislocations, grain boundaries
• Impurities

This rule is a basis for understanding the resistivity behavior of metals and alloys at low temperatures.

Mathematical Expression:

ρ = ρ_r + ρ_t

Where ρ = total resistivity

ρ_r = depends on structural defects

Concept:

The metals at the top of the activity series (K, Na, Ca, Mg and Al) are so reactive that they are never found in nature as free elements.

The metals in the middle of the activity series (Zn, Fe, Pb, etc.) are moderately reactive. They are found in the earth’s crust mainly as oxides, sulphides or carbonates.

Basis of reactivity, we can group the metals into the following three categories

1. Metals of low reactivity

(ii)Metals of medium reactivity

(iii)Metals of high reactivity.

 Different techniques are to be used for obtaining the metals falling in each category

Application:

The diagram shows the different techniques of extraction of metal from their ore.

A fuse is connected in series at the beginning of the circuit. The purpose of a fuse is to prevent overcurrent from damaging the load or other parts of the circuit. A series connection ensures that any current that enters the circuit passes through the fuse before reaching the load.

The image signal frequency is given by

f_si = f_Lo + f_IF

Where

f_LO = f_s + f_IF

Hence

f_si = f_s + 2.f_IF

f_si = 1000 + 2 (465)

• Reliance Jio Infocomm Ltd has overtaken Bharti Airtel to become the second-largest operator in terms of mobile subscriber base.
• The data was given by the Telecom Regulatory Authority of India.
• As of May end, Jio had 322.98 million users as against Airtel’s 320.38 million users.
• Vodafone Idea continues in the top position with 387.55 million users.

• Vikram Seth is the author of the book named ‘A Suitable Boy’.
• The novel revolves around the story of four families over a period of 18 months.

The two diodes are connected in reverse order to each other.

Here D1 is forward biased and D2 is reversed biased

D1 is replaced by short circuit and D2 is replaced by open circuit.

Current I_D becomes zero.

Current I_R is 0, and hence voltage drop across 5.6 kΩ resistor is 0, correspondingly V₀ = 0

When D2 is reversed biased, all the applied voltage +12 V appears across the diode.

V_D2 = 12 V.

A multipoint connection is also called as multidrop connection in which more than two specific devices share a single link.

In a multipoint environment, the capacity of the channel is shared, either spatially or temporally.

If several devices can use the link simultaneously, it is a spatially shared connection.

In ASK modulation each symbol is transmitted using a single bit

Hence, the bit rate = baud rate

Baud rate = 800 baud

If the question would have asked QPSK in case of ASK

Then QPSK transfers 2 bit for 1 symbol

Group velocity is the speed at which energy of wave travels in a medium while a phase velocity is the speed at which phase of any one frequency content of wave travels.