Sunday, June 16, 2019

Electrical Engineering RRB Technical Awareness questions and Answers.


01. As per ohm's law, what is potential
difference (V) equal to?

I.R.

SOLUTION
Ohm's law describes relationship between current and voltage in an ideal conductor

According to this law, potential difference (V) across an ideal conductor is proportional to current (I) passing through it.

Constant of proportionality is called resistance (R)
So, V=l.R.

02. Reaction between which of the followingtwo reactants will produce hydrogen gas?

Magnesium and
hydrochloric acid.

03. Which gas burns with popping sound?

Hydrogen

SOLUTION
· Hydrogen is a combustible gas
· Hydrogen gas is highly flammable that forms explosive mixtures with air
· The pop sound is due to small explosionformed by burning of hydrogen with
oxygen.

04. How can the sensitivity of a
potentiometer be increased?

By increasing the length
Of wire. 

SOLUTION 
The sensitivity of a potentiometer can be increased by increasing the length of the potentiometer wire and by reducing the current in the circuit by using a rheostat.

05. Plants are biotic as they are living beings.

Heat, Light and temperature are all abiotic factors as they are not living.

06. An object will continue to accelerate until

Resultant force on it is zero.

SOLUTION
An object continues to accelerate until itis stopped by an external force.

As per Newton's second law of motion,

F=ma

a = F/m

So, as per this law, when resultant forceon an object is zero,
Acceleration is zero.

07. When a magnetic needle is kept
in a non-uniform magnetic field, it
experiences?

A force and torque.

08. What is the use of CO2. Lasers in an
Industry?

Cutting and welding.

09. The water convert to water vapour at

100°C or 373 Kelvin.

10. The primary color in VDU (Visual Display Unit)

are RGB (Red, Green, Blue).

A VDU displays images generated by a computer or other electronic device.

11.  following communication modes support two-ways traffic but in only one direction at a time

Half-duplex.

12. In series LCR circuit, at resonance

current is maximum, power factor is unity.

13. The series magnet of a single phase Energy meter consists of coil of

thick wire of few turns.

14. The dummy coil in DC machines is used to

bring about mechanical balance of armature.

15. In an R-C-L series circuit, during
resonance, the impedance will be

minimum.

16. In interconnected grid system, more
efficient plants are used as

base load stations

SOLUTION
A base load station supplies almost a
constant load through out the day I. e. For24 hours. Therefore, more efficient plants are used as base load stations.

17. To supply peak load of a power station,

diesel power plants is very suitable.

SOLUTION
Peak load power stations deliver power for brief intervals in a day. Such stations must be put in service very quickly.

Consequently, they are equipped with
prime movers such as diesel engines and gas turbines that can be started up in a
few minutes. 

18. The voltage regulation of a d.c. generatoris zero. This implies that generator is

Flat compounded.

19. Which of following instruments has the highest torque/weight ratio among the given instruments?

Permanent magnet moving coil instrument.

20. What is the maximum number of lighting points that can be connected in a circuit?

Answer:- 10.

SOLUTION

At least 1 circuit for lighting. Each circuitsupplying a maximum of 10 lighting
points.

21. There are mainly three types of insulatorare used as overhead insulator like wise

Pin Insulator,
Suspension Insulator,
Strain Insulator.

22. In an alternator that  is the most dangerous fault and are likely to cause considerable damage to the expensive machinery

That is The stator winding faults.

23. A low lagging power factor results in

poor voltage regulation.

24. The demand factor on a power station is

always lesser than unity

SOLUTION
Demand factor = maximum demand /
Connected load

The demand factor is always lesser than unity because the maximum demand is always less than the connected load.

25. When the length of transmission line increases, the resistance (R) of the line

increases.

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Idioms mcq For Competitive Exams

Idioms mcq For Competitive Exams