RSMSSB JE Electrical Mock Test - 1 - Electrical Engineering (EE) MCQ

The correct answer is - Kunwar Man Singh of Amer

Key Points

• Kunwar Man Singh of Amer
  • Man Singh was a prominent Rajput noble in Emperor Akbar's court and a trusted general.
  • He held the highest Mansab (rank) of 7000, which was a significant honor and indicated high authority and responsibility.
  • He played a vital role in Akbar's military campaigns and administration, contributing to the stability and expansion of the Mughal Empire.

Additional Information

• Rai Singh of Bikaner:
  • He was a notable Rajput ruler and noble in Akbar's court.
  • While he held a significant position, he did not attain the highest Mansab like Man Singh.
• Raja Mansingh of Jodhpur:
  • Another significant Rajput noble but there is often confusion with Man Singh of Amer.
  • He held a high Mansab but not the highest under Akbar.
• Maharao Surjan Singh of Bundi:
  • A prominent ruler in Akbar's period, known for his loyalty.
  • Like the others, he held a substantial rank but not the highest.

The correct answer is Madhya Pradesh.

Key Points

• Inter-state border of Rajasthan:
  • Border of Rajasthan and Punjab – (89 km)
  • Rajasthan and Haryana border - (1262 km)
  • Rajasthan and Uttar Pradesh border – (877 km)
  • Rajasthan and Madhya Pradesh – (1600 km)
  • Border of Rajasthan and Gujarat – (1022 km)
• Length of the terrestrial boundary of Rajasthan
  • The total terrestrial extent of Rajasthan – is 5,920 km.
  • Length of the inter-state border – 4,850 km.
  • Length of International Border – 1,070 km.
    • Sriganganagar - 210 km
    • Bikaner - 168 km
    • Jaisalmer - 464 km
    • Barmer - 228 km​​

​

The correct answer is Jalore.

Key Points

• Moti bharat was introduced in the 19th century by mochi craftsmen.
• Moti bharat is a form of art unique to Rajasthan's Jalor area.
• By stringing together the opaque white beads in a variety of shapes and forms, including those of birds, animals, human figures, and other items of daily life, the opaque white beads serve as the foundation upon which the transparent beads are produced.
• Beads in the traditional colors of blue, green, yellow, and red were frequently utilized.
• The designs are frequently based on:
  • Stylized human figures
  • Geometric patterns
  • Scenes from daily life
  • Riders on horses and camels
  • An elephant pulling a haudha
  • A horse pulling a carriage
  • And the well-known legend of the local hero Dhola and his beloved Maru.
• A variety of items, including a purse, a hat, a toran, playthings, cradle decor, and showpieces are prepared by Moti Bhat.

The correct answer is option 4 i.e A-3, B-4, C-2, D-1.

Important facts to remember are:

=

The correct answer is Chand Baori - Abhaneri.

Key Points

• Chand Baori is a stepwell situated in the village of Abhaneri in the Indian state of Rajasthan.
• The state of Rajasthan is extremely arid, and the design and final structure of Chand Baori were intended to conserve as much water as possible.
• Chand Baori consists of 3,500 narrow steps over 13 stories.
• It extends approximately 30 m (100 ft) into the ground, making it one of the deepest and largest step-wells in India.

Additional Information

• Trimukhi baori
  • ​This ancient stepwell, named for its triple entrance, was built by the Shrimali Brahmins for rites and rituals associated with the mandir of Hanumanji.
  • This stepwell is located at a distance of 9 km from the city of Udaipur.
• Nulakha baori ​
  • ​It is situated in the Dungarpur district of Rajasthan.
  • It was built in 1586 AD by queen Premal Devi.
• ​Jhalibab baori
  • ​Jhalibab Bavri and Mamadev ka Kund is located at Kumbhalgarh fort in Rajsamand district near Udaipur of Rajasthan state It was built in the memory of Rana Kumbha. Both were built to store water.

The correct answer is Sandstone.

Key Points

• The great Vindhyan highland in central India consists of sedimentary rocks such as sandstones, shales, and limestones.
• The Vindhya range runs parallel to the Narmada-Son valley.
• The Vindhya Range is a complex, discontinuous chain of mountain ridges, hill ranges, highlands, and plateau escarpments in west-central India.
• The western end of the Vindhya range is located in the state of Gujarat, near the state's border with Rajasthan and Madhya Pradesh, on the eastern side of the Kathiawar peninsula.
• A series of hills connects the Vindhya extension to the Aravalli Range near Champaner.
• The Vindhya range rises in height east of Chhota Udaipur.​

Additional Information

• Sedimentary rocks
  • Sedimentary rocks are stratified consisting of many layers or strata and fossiliferous having fossils of plants and animals.
  • These rocks are generally porous and allow water to percolate through them.
  • Common sedimentary rocks include sandstone, limestone, and shale.

The correct answer is Bhavai.

Key Points

• The famous theatre director Shanta Gandhi was associated with Bhavai drama styles.
• Shanta Gandhi was born on 20-12-1917 in Nashik in the state of Maharashtra, India.
• She was an Indian Theatre Director, Dancer & Playwright known for her work in Gujarati and Hindi Cinemas.
• She was also a founder member of IPTA (Indian People's Theatre Association) & Avehi Abacus Project.
• She was also a Chairperson of NSD (National School of Drama), Delhi from 1982 to 1984.
• She received many government awards, including the Padma Shri (1984).
• A famous play written in Bhavai style is Shanta Gandhi's- Jasma Oden.

The correct answer is Jalore.

Key Points

• The first ropeway of Rajasthan was built in Sundha Hills, Jalore district.
• The hills are famous for Sundha Mata temple.
• The temple is devoted to the goddess Chamunda.
• It is located in the Jalore District of Rajasthan.
• The hills are located in the Aravalli ranges.
• The first ropeway of Rajasthan was built here.
• The temple was constructed by Deval Pratiharas with the help of the Chauhans of Jalore.​

Important Points

• The state government has recently promulgated a ropeway act and ropeway rules facilitating the establishment of ropeways.
• The following locations have been identified :
  • Kaisar - Kyari - Jaigarh
  • Savior Mandir-Pushkar
  • Taragarh (Ajmer)
  • Moti Magri - Sajjangarh Fort (Udaipur)
  • Scot office - Gaumukh (Mount Abu)
  • Jalore Fort (Jalore)
  • Kaolin Lake-machhiya Fort (Jodhpur)
  • Moosirani Chhatri Bala Kila-Alwar

The correct answer is Oriya.

Important Points

• Udiya or Oriya plateau is the highest (1360 meters) plateau of Rajasthan.
  • It is located in sirohi district.
• Abu-plateau is the second highest plateau of Rajasthan.
• Bhorat plateau is the third-highest plateau of Rajasthan
  • It is mainly a water flow divider between the Arabian sea and the Bay of Bengal.
• Uparmal plateau- A plateau part between Bijoliya and Bhainsrorgarh.

The correct answer is Sanskrit.

Key Points

• Ghosundi inscription is written in Sanskrit.
• The inscription of Ghosundi was obtained in the village of Ghosundi near Chittor.
  • The language used in this article is Sanskrit and the script Brahmi.
  • This article has been broken into many rocks. Only a few pieces of this are available. A large section of it is safe in the Udaipur Museum.
  • This inscription was first read by Dr Devdutt Ramakrishna Bhandarkar.
  • This is the most ancient inscription related to the Vaishnavite or Bhagavata sect in Rajasthan.

The correct answer is Waist.

Key Points

• A series of silver chains formed into a belt are worn at the hips and are generally known as kandora or kardhani, while the men would wear a silver or gold belt.
• Kandora ornament is worn on Waist.
• Kandora is similar to Kardhani but its design is different.

Additional Information

• Other important ornaments are:
• Head: Borla, Shishufal, Rakhdi, Tikadi, Sankali, Taawat.
• Hand: Takma, Patt, Punchiyan, Nogari.
• Waist: Kandori, Karghani, Tagadi, Satka.
• Foot: Payal, Nupur, Nevari, Lachha, Todia.

• The Hydro-electric power plant has the least maintenance cost among all types of power generation plants.
• Hydro-electric power plants not only have low maintenance costs but also have the least operating cost.
• Because Hydro-electric power plant has fewer-moving equipment, a rigid structure then the operating and maintenance cost reduces.
• Another factor in operations is the fuel cost which is practically free for hydro stations.
• Where a typical coal-fired plant is has a coal handling unit, a DM water unit, a generating unit, a cooling water unit, and an ash handling unit while a hydro plant has a generating unit only.

The permanent magnets are made from hard ferromagnetic materials (steel, cobalt steel, carbon steel etc). Since these materials have high retentivity, the magnet is quite strong. Due to their high coercivity, they are unlikely to be demagnetized by stray magnetic fields.

Permanent Magnets:

Permanent magnets are magnets with magnetic fields that do not dissipate under normal circumstances. They are made from hard ferromagnetic materials, which are resistant to becoming demagnetized.

Permanent magnets are made from a material that will inherit the properties of a strong magnetic field when exposed to it.

Properties:

Residual induction:

The residual induction is any magnetic induction that remains in a magnetic material after removal of an applied saturating magnetic field, measured in gauss or tesla. Residual induction is also known as magnetic remanence.

Coercivity:

• Coercivity (or the coercive field) is the property of a material to resist demagnetization due to the intensity of the material's magnetic field
• Coercivity is measured by the extent to which a demagnetizing field must be applied to reduce the material's magnetism to zero
• Permanent magnets are composed of materials with a high coercivity which retains their inherited magnetic fields under most conditions, unless intentionally demagnetized

Hysteresis loop:

• Wider hysteresis loops have high retentivity, coercivity, and saturation due to their larger hysteresis loop area
• These loops are typically found in hard magnetic materials
• Due to the size, these hysteresis loops have low initial permeability which leads to higher energy dissipation
• For these reasons, they are utilized in permanent magnets that have high resistance to demagnetization
• Demagnetization is more difficult to achieve in these wider hysteresis loops because there is a larger area to cover when reversing the hysteresis loop direction back to its original paramagnetic state

Note:

Diamagnetic materials

• Weak, negative susceptibility to magnetic fields
• Diamagnetic materials are slightly repelled by a magnetic field
• All the electrons are paired so there is no permanent net magnetic moment per atom
• Most elements in the periodic table, including copper, silver, and gold, are diamagnetic

Paramagnetic materials

• Small, positive susceptibility to magnetic fields
• These materials are slightly attracted by a magnetic field
• Paramagnetic properties are due to the presence of some unpaired electrons, and from the realignment of the electron paths caused by the external magnetic field
• Paramagnetic materials include magnesium, molybdenum, lithium, and tantalum

Ferromagnetic materials

• Have a large, positive susceptibility to an external magnetic field
• They exhibit a strong attraction to magnetic fields and can retain their magnetic properties after the external field has been removed
• Ferromagnetic materials have some unpaired electrons, so their atoms have a net magnetic moment
• Iron, nickel, and cobalt are examples of ferromagnetic materials.

• When the current carrying contacts of the circuit breaker are moved apart, an arc is formed, which insist for a short period after the separation of contacts
• This arc is dangerous on account of the energy generated in it in the form of heat which may result in explosive force
• The circuit breaker should be capable of extinguishing the arc without causing any disturbances to the equipment
• This phenomenon takes place at zero current
• There are two methods of arc extinction in circuit breakers; They are high resistance method and low resistance or zero current interruption method

Symmetrical components:

Any unbalanced system of n phasors can be resolved into the n-system of balanced phasors. These subsystems of balanced phasors are called symmetrical components. These are used in the analysis of unbalanced three-phase faults.

Positive sequence components:

Set of three phasors equal in magnitude, displaced from each other by 120° in phase, and having the same phase sequence as the original phasors constitute positive sequence components. They are denoted by suffix 1.

Negative sequence components:

Set of three phasors equal in magnitude, displaced from each other by 120° in phase, and having phase sequence opposite to that original phasors constitute the negative sequence component. They are denoted by suffix 2.

Zero sequence components:

The set of three phasors equal in magnitude and all phases (with no mutual phase displacement) constitute zero sequence components. They are denoted by suffix 0.

Concept:

Delta - Star Transformer:

In this type of connection in a transformer, primary side is connected in delta fashion while the secondary side is connected in star.

The main use of this connection is to step up the voltage i.e. at the beginning of high tension transmission system.

Also it is clear that there is a phase shift of 30° between primary line voltage and secondary line voltage.

Calculation:

Given:
11000/415 V delta-star transformer
Power rating (S) = 40 kVA
We know

I_L = Line current,
V_L =Line voltage
For primary side:


Now,
Voltage transformation ratio for transformer is

Short Trick:

As we know transformer transfers energy from primary to secondary. It cannot step up or step down energy because it will violate the law of transformer remains same.
Therefore, We can directly calculated the line current on the secondary side.
i.e.


I_L = 55.648 A

The power transfer capability of an AC transmission line is influenced by stability limit. The power transfer capability of existing transmission system can be enhanced through improvement of stability limits. Steady state stability limit is given by

Differential relay:

• Differential relay operation depends on the phase difference of two or more electrical quantities.
• It works on the principle of comparison between the phase angle and the magnitude of the same electrical quantities.
• The differential relay is used for the protection of the feeder, large busbars, etc.

Differential protection for feeders consist of
1) Voltage balance differential relay
2) Current balance differential relay

Note:
Generally Translay relay is used for feeder protection

• The translay relay is a differential relay
• The arrangement is similar to overcurrent relay, but the secondary winding is not closed on itself
• These types of relays are used in the feeder protection and the scheme is called Translay scheme
• In this scheme, two such relays are employed at the two ends of feeder as shown in the Fig

• The secondaries of the two relays are connected to each other using pilot wires
• The connection is such that the voltages induced in the two secondaries oppose each other
• The copper coils are used to compensate the effect of pilot wire capacitance currents and unbalance between two currents transformers
• Under normal operating conditions, the current at the two ends of the feeder is same
• The primaries of the two relays carry the same currents inducing the same voltage in the secondaries
• As these two voltages are in opposition, no current flows through the two secondaries circuits and no torque is exerted on the discs of both the relays
• When the fault occurs, the currents at the two ends of the feeder are different, hence unequal voltages are induced in the secondaries
• Hence the circulating current flows in the secondary circuit causing torque to be exerted on the disc of each relay
• But as the secondaries are in opposition, hence torque in one relay operates to close the trip circuit while in other relay the torque just holds the movement in unoperated position
• The care is taken that at least one relay operates under the fault condition

Concept:

• Ideally, a transformer draws the magnetizing current and lags the primary applied voltage by 90°.
• But the transformer also has a core loss current component which will be in phase with applied voltage.
• No-load current is nothing but the vector summation of these two currents.
• Hence, the no-load current will not lag behind applied voltage by exactly 90° but it lags somewhat less than 90°.
• It is in practice generally about 75°.

Additional Information

Circuit diagram for a transformer on no-load:

Where,
V1 is the applied primary voltage
Iw is the working component of current through Ro (Magnetizing resistance)
Iμ is the magnetizing component of current through Xo (magnetizing reactance)
N1 and N2 are primary and secondary turns ratio

• In the case of no-load, the second terminal of the transformer is open.
• There is no path available for the current to flow on the secondary side.
• Hence, the transformer does not draw current from the source.
• A small ampere of current flows through the primary transformer (no-load current I ) called excitation current (used for excitation of the core).
• No-load current (Io ) is further divided into Iw and Iμ.

Phasor diagram when transformer on no-load:

Concept:

The transfer function of a closed-loop system is given by:

where, C(s) = Output
R(s) = Input
G = Forward path gain
H = Feedback path gain

Explanation:

• 1 + GH is the characteristic equation of the transfer function.
• The roots of the characteristic equation are actually the zeroes of the characteristic equation.
• For the system to be stable, the number of zeroes of the characteristic equation on the right half of the S-plane must be 0.​

Additional Information

• The zeroes of the characteristic equation or the poles of the transfer function are the same thing.
• So for the system to be stable, the number of poles on the right half of the S-plane must be zero.
• This is the another condition of stability of the system.

The inverse transducer is defined as a device that converts an electrical quantity into a non-electrical quantity.

A piezoelectric crystal acts as an inverse transducer because when a voltage is applied across its surfaces, it changes its dimensions causing a mechanical displacement.

Note:

A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in pressure, acceleration, temperature, strain, or force by converting them to an electrical charge. It is used to measure displacement.

Concept:

Per unit quantity:

Per unit quantity = Actual quantity in the units / Base (or) reference quantity in the same units

⇒ Per unit impedance Zpu = Zactual / Zbase

⇒ Zpu = ZΩ × MVAb / (kVb)2

Conversion of one per unit impedance into another per unit impedance is given by

Autotransformer:

• An autotransformer is a type of electrical transformer with only one winding.
• In an autotransformer, one single winding is used as the primary winding as well as the secondary winding.
• In an autotransformer, the power is transferred from the primary to the secondary side through the induction and conduction process.

Power transfer in autotransformer:

a = v₁/v₂ = I₂/I₁
here, a is the voltage or turn ratio
Supply power on the primary side (P_P) = V₁I₁
Transferred power on the secondary side = V₂I₂
The power on the secondary is the sum of both i.e. inductive and conductive power.
The power which flows through the coil is the inductive power.
Inductive power (P_I) = V₂(I₁ - I₂) = I₁(V1 - V2)

Concept:
A DC generator is an electrical machine whose main function is to convert mechanical energy into electricity. When the conductor cuts magnetic flux, an emf will be generated based on the electromagnetic induction principle of Faraday’s Laws. This electromotive force can cause a flow of current when the conductor circuit is closed.

The emf equation of the DC generator is given by the equation:

where
Z = Total number of armature conductor
P = The number of poles in a generator
A = The number of parallel paths
N = Speed of armature in r.p.m
ϕ = Flux per pole
Lap winding
A = P
Wave winding
A = 2

Additional Information
Wave winding:

• In wave winding, the number of parallel paths is two
• This winding is mainly used for high voltage and low current applications

Lap winding:

• In lap winding, the number of parallel paths (A) is the same as the number of brushes and poles
• This winding is mainly used for low voltage and high current applications

Important Point

Concept:

The modulation index (β) in the frequency modulation is given by:

where, Δf = Frequency deviation

Δf_m = Maximum frequency deviation

The maximum frequency deviation in frequency modulation is 75 kHz.

(Δf_m)_max = 75 kHz

Carrier swing = f_max - f_min = 2Δf

Calculation:

Given, Carrier swing = 125 kHz

125 = 2Δf

Δf = 62.5 kHz

β = 83.3%

Key Points

• In a thyristor, Latching current (IL) is the minimum current needed to be attended by SCR to turn it ON.
• And Holding current IH is the minimum current above which must be continuously flown through it to keep it in an ON state.
• The Holding current(IH) is always less than the Latching current (IL)in a thyristor.
  

Astable multivibrator using 555 timers:

The voltage Vc across the capacitor varies between the upper threshold voltage (V_UT) and the lower threshold voltage (V_LT).

Calculation:

Given, V_cc = 9V

Resistance wire strain gauge:

The electrical resistance strain gauge is a resistance element that changes resistance when subject to strain or temperature change.

Gauge factor is defined as the ratio of per unit change in resistance to per unit change in length.

The relationship between the Gauge factor and Poisson's ratio is:

where, G_f = Gauge factor

v = Poisson's ratio

Resistance changes due to piezoresistive effects

Calculation:

Given, = 4.2

Neglecting resistance changes due to piezoresistive effects

4.2 = 1 + 2v

v = 1.6

Definition: Travelling wave is a temporary wave that creates a disturbance and moves along the transmission line at a constant speed. Such type of wave occurs for a short duration (for a few microseconds) but causes a much disturbance in the line.

The transient wave is set up in the transmission line mainly due to switching, faults and lightning.

Crest: It is the maximum aptitude of the wave, and it is expressed in kV or kA.

Front / Rise: It is the portion of the wave before the crest and is expressed in time from the beginning of the wave to the crest value in milliseconds or µs.

Tail / Fall: The tail of the wave is the portion beyond the crest. It is expressed in time from the beginning of the wave to the point where the wave has reduced to 50% of its value at its crest.
Polarity: Polarity of the crest voltage and value. A positive wave of 400 kV crest 1 µs front/rise and 50 µs tail/fall will be presented as +400/1.0/50.0 or 400/1/50.

Superconductor:

A superconductor is a material that achieves superconductivity, which is a state of matter that has no electrical resistance and does not allow magnetic fields to penetrate.

Properties of an ideal superconductor:

1.) Critical temperature / Transition temperature:

• The temperature below which the material changes from conductors to superconductors is called critical temperature or transition temperature.
• The transition from conductors to superconductors is sudden and complete.

2.) Zero Electric Resistance/Infinite Conductivity:

• In the superconducting state, the material has zero resistance. When the temperature of the material is reduced below the critical temperature, its resistance suddenly reduces to zero.

3.) Expulsion of Magnetic Field:

• ​Below the critical temperature, superconductors do not allow the magnetic field to penetrate inside them. This phenomenon is called Meisser Effect.

4.) Critical Magnetic Field:

• The certain value of the magnetic field beyond which the superconductors return to conducting state is called the critical magnetic field.
• The value of the critical magnetic field is inversely proportional to the temperature.
• As the temperature increases, the value of the critical magnetic field decreases.

5.) Magnetic Susceptibility:

The magnetic susceptibility of an ideal superconductor is -1.

The magnetic field of a superconductor is given by:

B = μ (1 + χ)

where, B = Magnetic field

μ = Permittivity

χ = Susceptibility

SInce, the magnetic field inside a superconductor is zero i.e.

B = 0

0 = μ (1 + χ)

χ = -1