Class 7 Heat and its Effect
Heat and its Effect
- In liquids, heat transfer takes place by
(d) none of these
- Some stainless steel frying pans are provided with copper bottoms. The reason for this could be that:
(a) copper bottom makes the pan more durable
(b) such pan appears colourful
(c) copper is a better conductor of heat than stainless steel
(d) none of these
- Transfer of heat by conduction process takes place in
(a) liquids only
(b) solids only
(c) gases only
(d) All of these.
- Heat energy from the sun reaches us by the process
(d) both a and b.
5.The woollen clothes keep us warm during winter because
A) wool is an insulator
B) wool is a conductor
C) wool traps air
D) wool has a vacuum.
(a) A and B
(b) B and C
(c) C and D
(d) A and C
- The transfer of heat by convection takes place in:
(a) Solids and liquids
(b) Solids and vacuum
(c) Gases and liquids
(d) Vacuum and gases
- The process which can transfer heat through the vacuum, as well as air, is:
- (c) convection
- (c) copper is a better conductor of heat than stainless steel
- (b) solids only
- (c) radiation
- (a) A and B
- (c) Gases and liquids
- (d) radiation
Fill in the blanks:
1.———- flows from a region of higher temperature to a region of lower temperature.
2.—–——– thermometer is used to measure our body temperature.
- Air is a————- conductor of heat.
- Shining and smooth surfaces are better —————-of heat.
- No medium is required for the transfer of heat by the process of————————-.
4. better reflectors
Very short Answer Question.
- State the unit in which temperature is commonly measured.
Ans. There are three units which are commonly used to measure the temperature: Degree Celsius, Fahrenheit and Kelvin.
- What is the usual temperature range of a laboratory thermometer?
Ans. A common laboratory thermometer can measure temperature from 10°C to 110°C.
This is called the range of a laboratory thermometer.
- What are the three methods of transfer of heat?
Ans. The three methods of transfer of heat are:
- By conduction method of transfer of heat
- By convection method of transfer of heat
- By radiation method of transfer of heat
- When one end of an Iron rod is heated its other end also becomes hot soon. Name the process by which heat flows in the rod?
Ans. By conduction method.
- What is the other name of poor conductors of heat?
Ans. Bad conductors of heat or Insulators.
- Name the two types of breeze which blow in coastal areas
Ans. land breeze and sea breeze
- Which method of heat transfer does not require any medium?
Ans. Radiation method of heat transfer does not require any medium
- A person sitting in front of a room heater feels hot. Name the process by which heat is transferred.
Ans. By convection method of heat transfer.