Important Questions Test: Heat - Class 7 MCQ

To measure temperature of human body we use clinical thermometer or doctor's thermometer.

The transfer of heat occurs as a wave in Radiation.

Explanation:

In conduction, heat is transferred through direct contact of particles. This usually occurs in solids where the particles are closely packed and can easily transfer energy through vibrations.

In convection, heat is transferred through the movement of fluids (liquids and gases). The heated fluid becomes less dense and rises, and the cooler, denser fluid sinks. This cycle leads to heat transfer.

In radiation, heat is transferred in the form of electromagnetic waves. These waves can travel through vacuum, unlike conduction and convection which require a medium (solid, liquid, or gas). Therefore, the transfer of heat as a wave occurs in radiation.

Aluminum is a good conductor of heat. Aluminum has a high thermal conductivity. Wood is a poor conductor of heat (as well as other forms of energy) because it is covalently bound as a compound.          

Explanation:
- Cold air moves from land towards sea during night: Land breeze occurs at night when the land cools down faster than the sea. As a result, the air above the land becomes cooler and denser, creating high pressure. The cooler air moves towards the warmer sea, creating a breeze that blows from the land towards the sea. This phenomenon is known as a land breeze.

At night, the land cools down faster than the water. The cooler air over the land moves towards the sea, which is called the land breeze.

• A metal plate due to its better thermal conductivity, draws heat faster from our hand than a plastic plate.
• This makes us feel that the steel plate is colder than the plastic one.

On a Fahrenheit scale:
(i) Boiling point of water is 212^∘F.
(ii) The temperature will be equal to that on the Celsius scale at −40^∘C.
(iii) The difference between the upper fixed point and the lower fixed point is divided into 180 equal parts.