Science [ 1 mark questions ]

People prefer white or light coloured clothes during summer as they are good reflectors of heat and hence, they keep us cool.

An earthen pot consists of small pores from which the water inside the pot constantly seeps out and gets evaporated due to the presence of high temperature around it. The evaporation process requires heat which is acquired from the surface of the pot, hence making the water and the pot cooler.

Ice is kept in a double-walled container so as to prevent melting of ice from the heat absorbed present in the immediate surroundings. The vacuum present in between the two walls prevents the transfer of heat from the first to the second wall and hence the ice remains in the solid form for a longer time period.

The process of transfer of heat in solids from a region of higher temperature to a region of lower temperature without the actual movement of molecules is called conduction.

Specific latent heat is the amount of heat energy absorbed or liberated by the unit mass of a substance during a change of state without causing any change in temperature.

Thus, latent heat is the amount of heat energy absorbed or released by a substance during a change in its physical states without any change in its temperature.

Th e process in which a solid is converted to a gaseous state is called sublimation.

Th e process in which a liquid is converted to vapor by absorbing heat is called boiling or vaporization.

The process in which a solid is converted to a liquid by absorbing heat is called melting or fusion.

The process of changing of a substance from one physical state to another at a definite temperature is known as change of state.

Heat capacity is the heat required to raise the temperature of the entire mass of the body by 1° C.

Specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of 1 kg of the substance by 1° C or 1 K.

Temperature is the degree of hotness or coolness of a body.

Radiation is a method of heat transfer that does not require particles to carry the heat energy.

Convection is the flow of heat through fluid from places of higher temperature to places of lower temperature by the movement of the fluid itself.

The process of transfer of heat in solids from a region of higher temperature to a region of lower temperature without the actual movement of molecules is called conduction.

Heat is a form of energy which transfers from the higher temperature region to the lower temperature region of a body.

The minimum possible temperature is OK. There is no limit to maximum temperature.

Joseph Black in 1750.

Temperature.

Thermos flask.

1 Calorie = 4.186 J
= 4.2 J

The amount of heat energy required to raise the temperature of 1 g water by 1°C is called one calorie.

Thermal capacity.

T(°C) = T(K) – 273.15
T(°C) = 80-273.15
T(°C) = 193.I5 °C

T(K) = T(°C) +273.15
= 35 + 273.15
T(K) = 308.15 K

T(°F) = (T(°F) × 1.8) + 32
= 40°C × 1.8 + 32
= 72 + 32
T(°F) = 104°F

T(°C) = (T(°F) – 32) /1.8
T(°C) = (100°F – 32)
T(°C) = 37.7 °C