Search Previous Year Questions

The correct answer is option 3):(Conduit wiring)

Concept:

• Electrical conduit provides very good protection to enclosed conductors from impact, moisture, and chemical vapors.
• Varying numbers, sizes, and types of conductors can be pulled into a conduit, which simplifies design and construction compared to multiple runs of cables or the expense of customized composite cables.
• Conduit wiring is more expensive but at least it will be neat looking and the conductors are safe from rats or damages inflicted by other workers
• It is a waterproof wiring system. It has a long life. It is a good appearance. Alternation is possible. It is reliable
• It requires a lot of holes in drywall to fish wires, and then each hole needs to be patched, painted, etc. It's also a difficult and potentially time-consuming job, as existing wiring, plumbing, etc gets in the way.

The correct answer is option 1): (Due to the gravitational pull of the Moon and the Sun)

Concept:

• Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and are also caused by the Earth and Moon orbiting one another. 

• Tides are very long-period waves that move through the ocean in response to the forces exerted by the moon and sun.

• Tides originate in the ocean and progress toward the coastlines where they appear as the regular rise and fall of the sea surface.

• When the highest part, or crest, of the wave, reaches a particular location, high tide occurs; low tide corresponds to the lowest part of the wave, or its trough.

• The difference in height between the high tide and the low tide is called the tidal range.

The correct answer is option 2):(voltage, frequency)

Concept:

• An infinite bus is a power system has its voltage and frequency remain constant. It is independent of real power and reactive power which is drawn from it or supplied to it.
• When an alternator is operating in parallel with an infinite bus and its excitation voltage is changed, the power factor of the machine changes.
• The model of the infinite bus bar is given as

​

The correct answer is option 4):(armature voltage control)

Concept:

The speed of an induction motor can be controlled from the stator side by changing;

• Applied voltage
• Applied frequency
• Number of stator poles

Speed Control by Changing Applied Voltage

• From the torque equation of the induction motor, the torque is directly proportional to the square of applied voltage.
• The slip at maximum torque is independent of the applied voltage. And also, the change in supply voltage does not change the synchronous speed.
• The below figure shows the torque-speed characteristics for changing values of the supply voltage.

The correct answer is option 3): Watt

Concept:

• Radiant flux or radiant power is the radiant energy emitted, reflected, transmitted, or received per unit time
• Radiant Flux (Φ) is energy per unit time (dQ/dt) that is radiated from a source over optical wavelengths
• The SI unit of radiant flux is the watt (W), one joule per second (J/s),
• The unit of spectral flux in frequency is the watt per hertz (W/Hz) a
• The unit of spectral flux in wavelength is the watt per metre (W/m)
• the unit of velocity is meter / second
• The lumen is a derived SI unit of luminous flux.

The correct answer is option 3): (Aluminum and Copper)

Concept:

• A cable lug is a component of an electrical device that connects the cable to the device terminals which simplifies the assembly of personnel, maintenance, and repair processes.
• A cable lug or connector is used when a permanent connection is required, but a direct one is inconvenient or impossible to achieve
• Mechanical lugs are mainly used to connect cables, Clamps that connect wires to an automotive battery is an easy example of lugs. They are made up of two metals – Aluminum  and copper.

The correct answer is option 1): (AC)

Concept:

• Wind turbines work on a simple principle, instead of using electricity to make wind, like a fan wind turbines use the wind to make electricity.
• The wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.
• The nature of electric power generated by wind turbine systems is AC
• The diagram for wind turbine is given as

The correct answer is option 1):(Voltage regulation)

Concept:

The voltage regulation of an alternator is defined as the rise in voltage at the terminals, when the load is reduced from full load rated value to zero, speed and field current remaining constant

It is given by the formula

\(\mathrm{Percentage:voltage:regulation =\frac{|𝐸_{𝑎}| − |𝑉|}{|𝑉|}× 100%} \)

Where,

|𝐸𝑎| is the magnitude of generated voltage (or no-load voltage) per phase

|𝑉| is the magnitude of full-load rated terminal voltage per phase

The voltage regulation of an alternator depends upon the power factor of the load, 

• An alternator operating at a unity power factor has a small positive voltage regulation.
• An alternator operating at a lagging power factor has a large positive voltage regulation.
• An alternator operating at lower leading power factors, the voltage rises with increase of the load and hence, the voltage regulation is negative.
• For a certain leading power factor, the full-load voltage regulation is zero. In this case, both the full-load and no-load terminal voltages are the same.

The correct answer is option 3):(MPPT)

Concept:

• MPPT is abbrvated as Maximum power point tracking algorithm
• This algorithm used to extract maximum power from the renewable source like solar energy
• To gain the maximum amount of power from the solar cell it should operate at the maximum power voltage. The maximum power voltage is further described by VMP, the maximum power voltage, and IMP, the current at the maximum power point

• The maximum power point (MPP) is the point on the current-voltage (I-V) curve of a solar module under illumination, where the product of current and voltage is maximum (Pmax, measured in Watts).

The correct answer is option 1): frequency

Concept:

Electric Fuses are proven to be helpful in safeguarding any Electrical appliance or household Circuits.

Its features are-

1. The melting points of Electric Fuses are very low, which is 200° C.
2. Fuse wires are made of an alloy composed of 50% lead and 50% tin.
3. The resistance of Fuse wires is so high that whenever its temperature rises and it reaches its melting point, it breaks the Current which passes through the Circuit. The conductance of the fuse is low
4. The rating of a fuse connected to the general household lighting circuit is 5A.
5. So the frequency is not characteristic of the fuse.