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4

The heat transfer from coolant to air in the radiator of an automobile engine takes place by

A. Radiation only

B. Convention only

C. Convection and radiation

D. Conduction, convection and radiation

Correct Answer :

C. Convection and radiation


Related Questions

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4

The main characteristics of a maintenance free (MF) battery is that

A. A maintenance free battery requires little maintenance during normal use and it is sufficient to add water instead of an electrolyte containing sulphuric acid

B. A maintenance free battery has a relatively short shelf life when compared with standard batteries

C. Since it is sealed, the water in maintenance free battery is not lost through evaporation thus accordingly it is not necessary to top up the cells with water

D. Recharging of a maintenance free battery is neither required nor possible

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4

The calorific value of petrol is about

A. 36.5-38.5 MJ/kg

B. 39.4-42.5 MJ/kg

C. 42.7-43.5 MJ/kg

D. 45.5-47 MJ/kg

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4

A three way catalytic converter

A. Re-circulates exhaust gases

B. Burns fuel vapour gases

C. Reduces N₂, H₂O, and CO₂ emission levels

D. Removes CO, HC, and NO₂ from the exhaust gasses passing through it

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4

The motion of the cam is transferred to the valves through

A. Pistons

B. Rocker arms

C. Camshaft pulley

D. Valve stems

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4

The aluminium alloy is used in cylinder blocks because

A. It is lighter and has good heat dissipation characteristics

B. Material cost is low

C. It does not require any cylinder liners

D. The piston is also made of aluminium alloy

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4

The starting system includes

A. A battery, a starter, and an ignition switch

B. A battery, a distributor, and an ignition switch

C. A battery, a starter, and a distributor

D. A distributor, a starter, and an ignition switch

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4

If clearance volume of I.C. engines is increased, the compression ratio will

A. Increase

B. Decrease

C. Remain constant

D. Be doubled

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4

The Diesel engine works on

A. Otto cycle

B. Carnot cycle

C. Diesel cycle

D. Rankine cycle

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4

The purpose of a thermostat in an engine cooling system is to

A. Prevent the coolant from boiling

B. Allow the engine to warm up quickly

C. Indicate the coolant temperature

D. Pressurise the system to raise the boiling point

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4

The rigid suspension is beneficial when

A. It is desired to reduce the unsprung mass

B. It is desired to have more flexibility in design

C. It is desired to improve tyre to ground contact characteristics

D. Large changes in load make it necessary to have a large suspension stroke

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4

The octane number of compressed natural gas (CNG) is

A. 90

B. 100

C. 110

D. 120

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4

The process of removing the burnt gases from the engine cylinder by the fresh charge coming into the engine cylinder from the crankcase, is known as

A. Cleaning

B. Priming

C. Scavenging

D. Detonation

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4

The information provided by the oxygen (O₂) sensor to the feedback control system is about the

A. Air-fuel ratio

B. Air temperature

C. Air flow speed

D. Exhaust gas volume

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4

The calorific value of Diesel is about

A. 36.5 MJ/kg

B. 38.5 MJ/kg

C. 42.5 MJ/kg

D. 45.5 MJ/kg

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4

The main merit of a multi cylinder type cylinder sleeve is

A. Smaller engine dimensions

B. Better cooling efficiency

C. High rigidity

D. None of these

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4

The engine oil viscosity is defined by _________ ratings.

A. Automatic transmission fluid (ATF)

B. Society of automotive engineers (SAE)

C. Gross vehicle weight (GVW)

D. American petroleum institute (API)

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4

During braking, the brake shoe is moved outward to force the lining against the

A. Wheel piston or cylinder

B. Anchor pin

C. Brake drum

D. Wheel rim or axle

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4

A worm gear is used as the pinion for the rack and pinion type of steering gearbox, because it

A. Improves steering comfort when steering wheel is turned to effect small changes in the direction of forward motion

B. Allows the steering wheel to be turned by a greater amount when steering

C. Makes the steering more responsive

D. Reduces the amount of kickback for large steering angles

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4

Cushioning springs in clutch plate reduces

A. Vehicle speed

B. Torsional vibrations

C. Jerky starts

D. None of these

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4

The minimum parking brake force is generally ________ of gross vehicle mass (GVM).

A. 5 %

B. 10 %

C. 15 %

D. 20 %

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4

The negative terminal post on the top of a battery is

A. Smaller than the positive terminal post

B. Larger than the positive terminal post

C. Of the same size as the positive terminal post

D. None of these

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4

The natural gas is compressed in a CNG cylinder at a pressure of

A. 200 bar

B. 220 bar

C. 250 bar

D. 300 bar

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4

The connecting rod is attached to the piston by the

A. Cap bolt

B. Piston pin

C. Cap roller bearing

D. Rod cap

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4

Valve overlap is the number of degrees of camshaft rotation during which

A. Both valves are closed

B. Both valves are open

C. Both 'A' and 'B'

D. None of these

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4

The materials used for cylinder block are

A. Cast iron and steel

B. Cast iron and aluminium alloy

C. Steel and aluminium alloy

D. Brass and steel

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4

The combustion process in a Diesel engine is a

A. Constant volume process

B. Constant pressure process

C. Constant temperature process

D. Adiabatic process

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4

The stroke of an engine is the

A. Volume of the cylinder

B. Length of the connecting rod

C. Internal diameter of the cylinder

D. Distance between T.D.C. and B.D.C.

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4

A battery can be charged by

A. Adding distilled water

B. Adding sulphuric acid

C. Applying voltage in the reverse direction to that of charging

D. Applying a voltage in the same direction to that of charging

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4

It is necessary to maintain the valve clearances as they

A. Reduce the resistance to sliding that occurs between the cam and the tappet

B. Allow for lengthening of the valves owing to the heat of combustion

C. Increase the speed at which the valves move up and down

D. Make the crankshaft turn smoothly

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4

The seat belt tensioners are built in the

A. Front seats

B. Shoulder anchors

C. Seat belt retractors

D. Seat belt buckles