FORCE AND PRESSURE, COAL AND PETROLEUM, COMBUSTION AND FLAME

Which Natural resource is used in the manufacturing of Steel?

• COAL TAR

• COAL GAS

• COKE

• ALL OF THESE

What is ignition temperature?

• Minimum temperature for a substance to catch fire

• Maximum temperature for a substance to catch fire

• Temperature needed for a burning substance to estinguish fire

• none of these

Calorific value is used

• for checking amount of fuel

• for calculating volume of fuel

• to check fuel efficiency

• to transport fuel from one place to other

What do you mean by explosion?

• a type of combustion

• a product of coal

• petroleum product

• none of these

A batsman hits a cricket ball which then rolls on the level ground. After covering a short distance

the ball comes to rest. The ball stops due to____________.

• magnetic force and electrostatic force

• friction and muscular force

• gravity and friction

• no force is applied to stop it

Name the force which do not act on the rocket

• muscular force

• atmospheric pressure

• gravity

• friction of air

rising ink in dropper is due to

• friction

• electrostatic force

• gravity

• atmospheric pressure

Why the cutting edge of a knife should be as sharp as possible?

• to increase friction

• to increase surface area of contact

• to increase atmospheric pressure

• none of these

What is easier- rolling or sliding?

• sliding

• rolling

• both are equal

• none of these

Which of the following is not an essential requirements for producing fire.

• combustible substance

• heat below ignition temperature

• presence of oxygen

• none of these