Test: Temperature & Heat - Class 7 MCQ

Celsius, Fahrenheit, and Kelvin are all temperature scales, while Newton is not.

Kelvin is commonly used in scientific measurements because it is an absolute temperature scale.

Mercury thermometers work by using the expansion of mercury in a glass tube to measure temperature.

The freezing point of water is 0°C on the Celsius scale.

Radiation is the transfer of heat through electromagnetic waves and does not require a medium for transfer.

Convection is the transfer of heat by the movement of fluids or gases.

Conduction is the transfer of heat through a material or between materials that are in contact with each other.

When heat is transferred by touching a hot object, it is transferred through conduction.

When warm air rises and cool air sinks, it is transferred through convection.

Heat can be transferred through a vacuum through radiation.

Metals are good conductors of heat because they have free electrons that can transfer energy quickly.

• Structure: Wood has a porous structure with many air pockets, which trap air. Air is a poor conductor of heat, making it effective at preventing heat transfer.

• Low Thermal Conductivity: The thermal conductivity of wood is low compared to metals, meaning it does not allow heat to pass through easily. This quality makes wood useful for thermal insulation in buildings and furniture.

• Natural Material: As a natural material, wood can also help in maintaining comfortable temperatures in homes, keeping them warm in winter and cool in summer.

The SI unit of heat is the joule.

When heat is transferred through a solid, it is transferred through conduction.

The boiling point of water is 100°C on the Celsius scale.

When heat is transferred through a liquid or gas, it is transferred through convection.

When heat is transferred by electromagnetic waves, it is transferred through radiation.

The formula for calculating heat energy is Q = m × c × ΔT, where Q is the heat energy, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature.

When heat is transferred through a material by the movement of electrons, it is transferred through conduction.

Heat loss can be prevented by using insulation, wearing warm clothing, and closing windows and doors.