681. The frequency of flashing of light per minute in a direction (side turn) indicator is about
A. 9
B. 90
C. 900
D. 9000

682. Thinner is added to the paint in order to
A. make pigments and resin mix easily
B. make paint film hard
C. optimise its viscosity
D. none of these

683. For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of
A. copper
B. aluminium
C. steel
D. brass

684. The ease with which petrol vapourizes is called its
A. oxidation
B. octane number
C. volatility
D. cetane number

685. A four-cylinder engine has a capacity of 2.4 litres. The swept volume of one cylinder is
A. 400 cm3
B. 600 cm3
C. 1200 cm3
D. 2400 cm3

686. An imbalance wheel during vehicle operation
A. makes large noise when its heavy point hits the road surface
B. deflects in the vehicle’s longitudinal direction
C. bounces vertically or deflects from side to side (as seen from front or rear)
D. creates a standing wave

687. The main function of the brake fluid is
A. lubrication
B. power transmission
C. cooling
D. none of these

688. The parking brakes employed in vehicles are operated
A. mechanically
B. hydraulically
C. pneumatically
D. none of these

689. The function of a carburettor is to control the amount and ratio of air-fuel mixture.
A. True
B. False

690. The component in the radiator of an automobile that increases the boiling point of water is
A. drain plug
B. water jacket
C. vacuum valve
D. pressure cap

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