RRB JE ECE (CBT II) Mock Test- 3 - Electronics and Communication Engineering (ECE) MCQ

n-bit Johnson ring counter has 2n states.
Thus, if a Johnson counter has n states then the number of flip flops required are N/2.

• The Constitution of India was adopted by the Constituent Assembly on 26^th November, 1949 but it came into force on 26^th January, 1950.
• Constitution of India is known as the supreme law of India which consists of fundamental political codes, powers, procedures, structures and the duties of the government institutions, directive principles and the duties of the citizen.
• It is the longest written constitution of any country in the world.
• B.R. Ambedkar was considered to be its chief architect as he was the Chairman of the Drafting Committee. 

Analog transducers:

• These transducers convert the input quantity into an analog output which is a continuous function of time
• Thus, a strain gauge, an L.V.D.T., a thermocouple or a thermistor may be called as Analog Transducers as they give an output which is a continuous function of time

Digital Transducers:

• These transducers convert the input quantity into an electrical output which is in the form of pulses and its, output is represented by 0 and 1

Lower 8 pins of microprocessor pins are multiplexed to act for data or address transfer.

Whether the bus is used to carry data or address is decided by the signal on ALE pin.

When

ALE = 1 address is transferred to bus

• Message: The message is the information (data) to be communicated; Popular forms of information include text, numbers, pictures, audio, and video
• Sender: The sender is the device that sends the data message; It can be a computer, workstation, telephone handset, video camera, and so on
• Receiver: The receiver is the device that receives the message; It can be a computer, workstation, telephone handset, television, and so on
• Transmission medium: The transmission medium is the physical path by which a message travels from sender to receiver; Some examples of transmission media include twisted-pair wire, coaxial cable, fiber-optic cable and radio waves
• Protocol: A protocol is a set of rules that govern data communication

For a RADAR the duty cycle is given by:

Duty cycle = Pulse width × pulse repetition frequency

D = 1 × 10^-6 × 1500 = 0.0015

In ammeters, the range can be extended by using low shunt resistance. As low shunt resistance is connected in parallel, the meter resistance will get reduce.

In voltmeters, the range can be extended by using high series resistance. As high series resistance is connected in series, the meter resistance will get increased.

Concept:
The reflection coefficient gives the percentage of incident voltage reflected from the load.
Mathematically
reflection coefficient = 
Where Z_L is the load impedance and Z_o is the characteristic impedance.
Application of Concept:
For open circuit transmission line
Z_L = infinite
reflection coefficient = 
As Z_L → ∞
Reflection coefficient = 1

An amplifier cannot discriminate between the intended signal and noise; it amplifies equally everything fed into it. A repeater dots not amplify the signal; it regenerates the signal. When it receives a weakened or corrupted signal, it creates a copy, bit for bit, at the original strength.

A repeater forwards every frame; it has no filtering capacity.

The Truth table of JK flip flop is

From the truth table when J = 0, K = 1 the output is reset, i.e. Q_{n + 1} = 0

Nonbiodegradable chemicals are most harmful environmental pollutants as these cannot be broken down into simpler, harmless substances in nature. Whereas, biodegradable pollutants can be rapidly decomposed into simpler and harmless substances by natural processes.

In star to delta transformation
R_a = R₂ + R₃ + R₂R₃/R₁
R_b = R₁ + R₃ + R₁R₃/R₂
R_c = R₁ + R₂ + R₁R₂/R₃

Structure of the atmosphere

The atmosphere is divided into five layers starting from the earth's surface:

Troposphere (0 - 18 km): This is the most important layer of the atmosphere. The air breath exists here. All the weather changes like rainfall, fog, and hailstorm occur in this layer.

Stratosphere (18 - 50 km): It is free from clouds which makes it the most ideal layer for flying Aeroplanes. It contains a layer of ozone gas which protects from the harmful effect of the sun rays.

Mesosphere (50 - 85 km): It is the third layer of the atmosphere. Temperature drops to about -95°C. The mesosphere is the coldest region of Earth’s atmosphere. 

Thermosphere (85 - 500 km): In this layer, the temperature rises very rapidly with increasing height. The ionosphere is a part of this layer. It helps in radio transmission.

Exosphere (500 - 1600 km): The uppermost layer of the atmosphere is called exosphere. It is very thin air. Temperature is very high due to direct solar radiation. Light gases like Helium and Hydrogen float into space from here.

Total space charges per unit area in P-side must be equal to n-side as per the space charge neutrality.

N_A x_po = N_D x_no

Hence, the correct option is (D)

If there is n-bit address bus, then number of memory locations are 2^N
Thus for 8-bit address line number of memory locations are 2⁸= 256
Hence, the correct option is (C)

A data communication system has five components:

Message: The message is the information (data) to be communicated; Popular forms of information include text, numbers, pictures, audio, and video

Sender: The sender is the device that sends the data message; It can be a computer, workstation, telephone handset, video camera, and so on

Receiver: The receiver is the device that receives the message; It can be a computer, workstation, telephone handset, television, and so on

Transmission medium: The transmission medium is the physical path by which a message travels from sender to receiver; Some examples of transmission media include twisted-pair wire, coaxial cable, fiber-optic cable and radio waves

Concept:

SRAM can retain stored data indefinitely and it can be implemented as a flip flop circuit to store one bit of information.

DRAM uses a single transistor to access the capacitor charge. Since stored charge is gradually lost because of leakage capacitance associated with them, the cells require periodic refreshing.

Difference between SRAM and DRAM:

Array:

• An array is a group (or collection) of same data types.
• For example, an int array holds the elements of int types while a float array holds the elements of float types.
• Non-homogenous data elements cannot be stored in array.

Records:

• In database management systems, records are composed of fields, each of which contains one item of information.
• A set of records constitutes a file.
• For example, a personnel file might contain records that have three fields: a name field, an address field, and a phone number field.

Records is not a data structure.

Pointers:

A pointer is a variable that stores the address of another variable. Unlike other variables that hold values of a certain type, pointer holds the address of a variable.

Pointer is a primitive data type and is homogenous data structure.

Stack:

Stack can be implemented using array or linked list.

When stack is implemented using link list then it can store non homogeneous data when it is implemented using array it stores homogeneous data structure.

Concept:

The compounds are characterised by their functional group:

1. Aldehyde:

These compounds have R -CHO as their functional group.

2. Ketone:

These compounds are characterised by  R-CO- R type of functional groups where R is alkyl chain.

3. Acid:

Compounds containing R-COOH group at the end are called carboxylic acids

4. Alcohols:

Alcohols have -OH group attached to its end.

Application:

From the above discussion only Carboxylic Acid group have 2 oxygen atoms.

The given compounds can be written as:

CH₃ – CH₂ – COOH

Which is chemical formula for Propanoic acid.

When the quantity of acids in the raining water is more than the average, then such rain is called 'Acid rain'.

We are aware that normally rainwater has a pH of 5.6.  When the pH of the rainwater drops below 5.6, it is called acid rain.

Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth’s surface. Oxides of nitrogen and sulphur which are acidic in nature can be blown by the wind along with solid particles in the atmosphere and finally settle down either on the ground as dry deposition or in water, fog and snow as wet deposition.

The bad effects of acid rain

• When acid rain falls and flows as groundwater to reach rivers, lakes etc, it affects plants and animal life in the aquatic ecosystem
• Acid rain is harmful to agriculture, trees and plants as it dissolves and washes away nutrients needed for their growth
• It causes respiratory ailments in human beings and animal
• It may also cause corrosion in many buildings bridges, monuments, fencing etc
• It causes irritation in the eyes and skin of human beings
• This rain reduces the lustre of the metals too
• Acid rain damages buildings and other structures made of stone or metal
• The Taj Mahal in India has been affected by acid rain

The low pass circuit is shown below:

V_i = V_R + V_C

V_R = i_R

Current through capacitor is given by

As time constant is large

RC > 1

The output voltage is integral of input voltage and hence the low pass filter acts as integrator.

Characteristics of Data Communication:

The effectiveness of any data communications system depends upon the

following four fundamental characteristics:

Delivery:

The data should be delivered to the correct destination and correct user.

Accuracy:

The communication system should deliver the data accurately, without introducing any errors. The data may get corrupted during transmission affecting the accuracy of the delivered data.

Timeliness:

Audio and Video data has to be delivered in a timely manner without any delay; such a data delivery is called real time transmission of data.

Jitter:

It is the variation in the packet arrival time. Uneven Jitter may affect the timeliness of data being transmitted.

MVI H, 40 H     // H ← 40 H

MVI L, 20 H     // L ← 20 H

SHLD means store the content of HL pair directly to memory address

Following the “little endian rule”, the data from lower order register will go to lower order address and data from higher order register will go to higher order address

SHLD 5000   

5000 ← L

5001 ← H 

Inductance of a coil is proportional to square of number of turns

L ∝ N²

Given N ↑2 times

∴ New inductance L₂ = 4 L₁ = 4 × 1 = 4 mH

Concept:

Hall Voltage states that if a specimen (metal or semiconductor) carrying a current I is placed in transverse magnetic field B, an electric field is induced in direction perpendicular to both I and B.

Hall Voltage is given by:

V _H = Ed = B I/pW

Applications of Hall effect:

Hall effect can be used to find:

1. Carrier concentration

2. Type of semiconductor

3. Conductivity

4. Mobility

It cannot be used to find magnetic field.

8085 has 74 instruction. Out of 74 instructions 72 are used for operation between memory and microprocessor and 2 are used for the transfer of data between microprocessor and I/O device.

IN, 8bit address

The content of the input port whose address is given is read and loaded into the accumulator.

OUT, 8bit address

• The Images formed by the Plane Mirror are laterally inverted, virtual and erect.
• Plane mirrors are used in looking glasses, Solar Cooker etc.
• If an object moves with a certain velocity towards a plane mirror then its image appears to be moving with twice the velocity it was moving towards the mirror.

• Hinako Shibuno of Japan won the Women’s British Open by one shot over Lizette Salas on 4 August 2019.
• She played for the first time outside of her country and birdied five of the final nine holes in a 4-under 68 and 18-under 270 overall.
• Morgan Pressel (67) finished fourth at 15 under, just ahead of former leader Ashleigh Buhai (70).

Start with hydrogen since it occurs in only one compound on each side of equation

Hydrogen on LHS = x

Hydrogen on RHS = 4

Replace x by 4

Cu + 4 HNO₃ → Cu(NO₃ )₂ + y NO₂ + 2 H₂O

Now balance nitrogen

Nitrogen on LHS = 4

Nitrogen on RHS = 2 + y

Replace y by 2

Cu + 4 HNO₃ → Cu(NO₃ )₂ + 2 NO₂ + 2 H₂O

• The Indian name of Ursa Major constellation or Great Bear constellation is 'Saptarishi'.
• The Ursa Major constellation consists of 7 bright rishis (stars) and these rishis become the 7 stars of the BIG DIPPER constellation.
• Ursa Major is visible throughout the year from the northern hemisphere.