Question 1

Which of the following has the highest value of thermal conductivity?

Accepted Answer

Solid ice has the highest thermal conductivity among the options given. In general, solids tend to have higher thermal conductivity than liquids and gases because their molecules are closer together, allowing heat to transfer more efficiently through vibration and conduction mechanisms.

Question 2

The basic electrical requirement in arc welding is that there should be

Accepted Answer

High open-circuit voltage is a basic electrical requirement in arc welding because it helps to initiate and maintain the arc.

Question 3

A.C. welding machine cannot be used for welding

Accepted Answer

A.C. welding machine cannot be used for welding MIG welding because MIG welding requires a direct current (DC) power source.

Question 4

In electric welding, arc blow can be avoided by

Accepted Answer

Arc blow is minimized by using alternating current (AC) welding machines because the alternating nature of the current helps to balance the magnetic fields that cause arc blow, reducing its effects.

Question 5

The major disadvantage of carbon arc welding is that

Accepted Answer

The answer of The major disadvantage of carbon arc welding...

Question 6

The free-running speed of a train does NOT depend on the

Accepted Answer

The answer of The free-running speed of a train does...

Question 7

Longer coasting period for a train results in

Accepted Answer

A longer coasting period for a train means it is utilizing its momentum to travel without additional power, which reduces the amount of energy consumed per distance traveled, leading to lower specific energy consumption.

Question 8

Skidding of a vehicle always occurs when

Accepted Answer

Skidding occurs when the braking effort exceeds the adhesive weight, meaning the friction between the tires and the road is not enough to prevent sliding.

Question 9

In India diesel locomotives are manufactured at

Accepted Answer

Diesel locomotives in India are manufactured at the Diesel Locomotive Works (DLW) in Varanasi.

Question 10

The horsepower of steam locomotives is

Accepted Answer

The answer of The horsepower of steam locomotives is
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Question 11

In tramways which of the following motors is used?

Accepted Answer

DC series motors are commonly used in tramways due to their high starting torque and ability to handle varying loads, which is essential for vehicles that start and stop frequently.

Question 12

In a steam locomotive electric power is provided through

Accepted Answer

Steam locomotives can be equipped with a small turbo-generator to provide electric power for lighting and other auxiliary systems. This device generates electricity by using steam from the locomotive's boiler to drive a small turbine connected to an electrical generator.

Question 13

Which of the following drives is suitable for mines where explosive gas exists?

Accepted Answer

Battery locomotives are suitable for mines with explosive gases because they do not produce flames or sparks that could ignite the gas, unlike steam and diesel engines.

Question 14

In case of locomotives the tractive power is provided by

Accepted Answer

Locomotives, especially steam locomotives, commonly use a double cylinder, double acting steam engine. This configuration allows for more efficient use of steam, providing power on both the push and pull of the piston in each cylinder, which results in smoother and more continuous tractive effort.

Question 15

which of the following track is electrified

Accepted Answer

The answer of which of the following track is electrified
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Question 16

For which of the following locomotives the maintenance requirements are the least?

Accepted Answer

Electric locomotives generally require less maintenance than steam or diesel locomotives. This is because electric locomotives have fewer moving parts and do not require fuel handling systems or combustion engines, which are present in steam and diesel locomotives and necessitate more frequent maintenance.

Question 17

For 600 V D.C. line for tramcars, brack is connected to

Accepted Answer

The brake in a tramcar system is typically connected to the negative of the supply. This is because the negative side is often used as the return path for the electrical current, making it a more suitable point for braking mechanisms that may require grounding or a return path for the electrical circuit to function properly.

Question 18

In case of---------free running and coasting periods are generally long.

Accepted Answer

Main-line service typically involves longer distances between stops, allowing for longer periods of free running and coasting.

Question 19

The return circuit for tram cars is through

Accepted Answer

The return circuit for tram cars is typically through the rails. The rails act as a return path for the electrical current, allowing it to complete the circuit back to the power source. This is a practical and efficient method for grounding and completing the circuit in tram systems.

Question 20

Fuse is a piece of wire of a materi

Accepted Answer

Fuses are made of materials with a low melting point so that they melt and break the circuit when excessive current flows through, preventing damage to the electrical system.

Quiz 3: Thermal Conductivity, Welding, and Locomotives