World GK Questions and answers pdf - 1

Question: 1

What is freezing mixture?

A mixture of compound that produces a low temperature is called freezing mixture.

The freezing mixture of salt and ice is in the ratio 1:3.

Question: 2

Define vapourisation and condensation?

Vapourisation : The process in which a liquid changes into vapour on heating is called vapourisation (e.g) water changes into water vapour or steam.

Condensation : When vapour condenses to form a liquid, the change of state is called condensation (e.g) steam changes to water.

Question: 3

Define specific heat capacity?

The specific heat capacity of a substance is the amount of heat required to raise the temperature of 1 Kg of a substance by 1°C. The unit of specific heat capacity is joule per kilogram per Kelvin or J/kg/K.

Question: 4

Define joule?

The amount of heat energy required to raise the temperature of 1 gram of water through 1°C is called 1 calorie. The amount of heat energy required to raise the temperature of 1 kg of water through 1&Deg;C is called 1 kilocalorie.

1 calorie ⇒ 4.2 joules

1 kilo calorie ⇒ 4.2 x 1000 = 4200 joule.

Question: 5

What is called fuel?

Materials which produce heat when burnt are called fuels. Coal, petrol, cooking gas etc are fuels.