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

The feedback factor is given by β

100 R₂ = 30 R₁ + 30 R₂
70 R₂ = 30 R₁
7 R₂ = 3 R₁

Offset error:

It is defined as a constant difference, over the whole range of the ADC, between the actual output value and the ideal output value.

Gain error:

It is defined as the difference of the slope of the actual output values and the ideal output values.

Non-linearity error

• The optical properties of liquid crystals depend on the direction of light travels through a layer of the material
• In LCD, the electric field is induced by a small electric voltage applied across it; Due to which the orientation of molecules in a layer of liquid crystals can be changed

• 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

• Residual resistivity is the resistivity of material at 0 kelvin
• It depends on the imperfections in the lattice
• It is independent of temperature

In constant current charging method, the battery is supplied with constant current throughout its charging period. Through this method, the charging is fast initially but slows down near high values of battery charge.

For n-bit ADC of different type the conversion times are as follows –

Counter type (T_A) = 2ⁿ T_CLK

Dual slop (T_B) = 2ⁿ⁺¹ T_CLK

SAR type (T_C) = n T_CLK

Flash type (T_D) = T_CLK

Different types of oscillators are:
1. LC Oscillators:

• Colpitts Oscillator
• Clapp's Oscillator
• Hartley Oscillator

2. RC Oscillators

• Wein Bridge Oscillator
• RC Phase shift oscillator

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.

The colour of different pH indicators in different mediums is summarized in the table below:

There are two basic methods of measurement:

1. Direct comparison with either a primary or a secondary standard

2. Indirect comparison using calibrated system

Direct measurements: The value of the physical parameter (measurand) is determined by comparing is directly with reference standards. The physical quantities like mass, length and time are measured by direct comparison.

Indirect measurements: The value of the physical parameter (measurand) is more generally determined by indirect comparison with secondary standards through calibration.

The measurand is converted into an analogue signal which is subsequently processed and fed to the end device that presents the result of measurement.

Primary measurements: The value of the physical parameter is determined by comparing directly with the reference standards. The required information is obtainable through senses of sight and touch.

Ex: Matching of two lengths when determining the length of an object with a ruler

Secondary and Tertiary measurements:

An indirect method may consist of developing an electrical voltage proportional to a physical value to be measured, measuring that voltage and then converting the measured voltage back to the corresponding value of the original measurand.

Electrical methods are preferred in the indirect methods due to their high speed of operation and simple processing of the measured variable.

The indirect measurements involving one conversion are called secondary instruments and those involving two conversions are called tertiary measurements.

Examples of secondary instruments:

The conversion of pressure into displacement by means of bellows

The conversion of force into displacement by means of springs

The pressure measurement by manometers and the temperature measurement by mercury in glass thermometers etc

Examples of tertiary measurements:

Measurement of pressure by a bourdon tube pressure gauge

Measurement of angular speed by an electric tachometer

Primary cells: It is a cell that once it has been discharged, cannot be recharged. Primary cells are called as dry cells because they have solid or molten electrolyte.

These are light in weight and have less cost.

Secondary cells: It is the one that can be electrically recharged after use to their original pre-discharge condition. Normally secondary cells are wet cells.

These are heavy in weight and have high initial cost.

For turning off the SCR anode current must fall below the holding current.

Turn-off time of a thyristor effects it’s operating frequency because turn off time of thyristor is inversely proportional to frequency.

The turn – off time is divided into two intervals: reverse recovery time t_rr and the gate recovery time t_gr

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.

The Internet Message Processor (IMP) was the packet switching node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of gateways, which are known today as routers.

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)

Effective modulation index, 
We have μ1 = 0.3 and μ2 = 0.4
Thus, 
In percentage,μ = 50%
Hence, the correct option is (A)

• In signed float 2const, signed is modifier and float data type 2const is identifier
• An identifier should not start with a number but identifier 2const is starting with 2(number) hence it will give an error

Hence, the correct option is (C)

Tebhaga movement in Bengal was militant campaign initiated by Kisan Sabha in 1946. During that period, share-cropping peasants had to give half of their share of harvest to Jotedars who were the owners of land. They demanded reduction in distribution of harvest share given to landlords to only one-third the price, which seems to be option A.
Hence, the correct option is (A)

Applying source transformation

Apply KVL:
(since the loop is not closed there will not be any current flow)
V_A - 1 - 4 + 9 = V_B
V_A + 4 = V_B
V_AB = V_A - V_B = - 4V

• Kudremukh National park is located in Chikkamagaluru district of Karnataka.
• It was declared as a National Park in 1987.
• Other famous National parks in Karnataka are Bandipur, Nagarhole, and Anshi National Park.
• Famous National Parks in Kerala are Periyar, Silent Valley, and Anamudi Shola National Park.
• Famous National Parks in Tamil Nadu are Mudumalai, Mukurthi, and Indira Gandhi National Park.
• Famous National Parks in Odisha are Simlipal, and Bhitarkanika National park.

Concept:
V _bi = V ₀ =  = Built in Potensial 
Application:
N_A N_D = 25 x 10¹⁴
 = 25 x 10¹⁴
Here N_A N_D =  hence we have
V ₀ = KTLn(₁) = 0 V

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.

The following table shows the masking of hardware interrupts

From the above table INTR can be disabled by DI but cannot be masked using SIM.

We know that, R = p^l / A
Cross sectional area is more for thicker wire. As area is inversely proportional to resistance, the resistance of a thicker wire is low.
As wires are connected in series, same current flows through both the wires.
Heat produced by the current I is given by I­²R.
As same current flows through both the wires, more heat produced in the high resistive wire. Thus, heat produced by the current is more for the thinner wire.
Hence, A is false, and R is true.

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.

• The 20th Anniversary of Kargil Vijay Diwas was celebrated on 26 July 2019. 
• The day is named after the successful Operation Vijay in 1999, when India regained the control of the high outposts which had been stealthily taken over by Pakistan.
• The celebrations of 20th Anniversary of Kargil Vijay Diwas began in Delhi on 14 July 2019.

Concept:

• Esters are sweet-smelling substances.
• These are used in making perfumes and as flavouring agents.
• Esters react in the presence of an acid or a base to give the alcohol and salt.
• This reaction is known as saponification because it is used in the preparation of soap

Underlying reaction:

CH₃COOC₂H₅ + N aOH → C ₂H ₅OH + C H ₃COON a

Concept:

Metals react with oxygen to form metallic oxides.

These metallic oxides are basic in nature

Metal + Oxygen → Metallic oxide

Example:

When magnesium burns in air it combines with the oxygen of the air to form magnesium oxide

2 Mg + O₂ → 2 MgO

Magnesium oxide dissolves in water to form magnesium hydroxide solution

MgO + H₂O → Mg(OH)₂

The prescribed permissible noise level for the residential area is 55 and 45 decibels during daytime and night-time respectively.

Important Points:

• The prescribed permissible noise level for silence zones is 50 and 40 decibels during daytime and night-time respectively
• The prescribed permissible noise level for the industrial area is 75 and 70 decibels during daytime and night-time respectively
• The prescribed permissible noise level for the commercial area is 65 and 55 decibels during daytime and night-time respectively