Question

1. cotton clothes are made from() fibres. a) animal b) plant c) synthetic answer in one or two sentences. 1. how does convection current take place in air? 2. why digital thermometer is convenient to use these days? 3. what are conductors? write two examples answer the following questions in detail. 1. how are land and sea breeze caused? 2. we wear woollen clothes in winter. explain 3. explain with the help of an illustration three modes of heat transfer.

Explanation:

1. Convection current in air occurs when warmer, less - dense air rises and cooler, denser air sinks, creating a continuous circulation.
2. Digital thermometers are convenient as they provide quick, accurate readings, are easy to read and sanitize.
3. Conductors are materials that allow heat or electricity to pass through them easily. Examples: Copper, Aluminum.
4. Land and sea breezes are caused by the differential heating and cooling of land and water. During the day, land heats up faster than water, so air over land rises and cooler air from the sea moves in (sea - breeze). At night, the land cools faster, and air over the sea is warmer, so air moves from land to sea (land - breeze).
5. We wear woollen clothes in winter because wool is a poor conductor of heat, which traps air pockets and provides insulation, keeping our body warm.
6. The three modes of heat transfer are conduction (transfer of heat through direct contact, e.g., a metal spoon in a hot soup getting warm), convection (transfer of heat through the movement of fluids, e.g., hot air rising in a room), and radiation (transfer of heat through electromagnetic waves, e.g., feeling the warmth of the sun).

For the multiple - choice question: Cotton clothes are made from plant fibres.

Answer:

b) plant

1. How does convection current take place in air? Warmer, less - dense air rises and cooler, denser air sinks, creating a circulation.
2. Why digital thermometer is convenient to use these days? It provides quick, accurate readings and is easy to read and sanitize.
3. What are conductors? Write two examples. Conductors are materials that allow heat or electricity to pass through easily. Examples: Copper, Aluminum.
4. How are land and sea breeze caused? Due to differential heating and cooling of land and water. Sea - breeze during the day and land - breeze at night.
5. We wear woollen clothes in winter. Explain. Wool is a poor heat conductor, traps air for insulation.
6. Explain with the help of an illustration three modes of heat transfer. Conduction (direct contact), convection (fluid movement), radiation (electromagnetic waves).