Class 7 Science Chapter 3 Question Answers - Heat

Q1: Define temperature.
​Ans: The measure of hotness or coldness of an object is called temperature. It is usually measured in "degrees". 

Q2: Name the device used to measure temperature.
Ans: A thermometer is a device used to measure temperature. 

Thermometer

Q3: Name the two types of thermometers.
​Ans:  Clinical thermometer and laboratory thermometer.

Q4: What do you mean by clinical thermometer?
​Ans: The thermometer used to measure our body temperature is called a clinical thermometer.

Q5: The bulb in the thermometer contains _____________.
​Ans:  Mercury

Q6: Thermometer should be washed before and after use with, preferably with an _________ solution.
​Ans:  Antiseptic solution

Q7: Before use, the mercury level of the thermometer should be below __________.
Ans:  35°C

Q8: We should hold the thermometer by the bulb while holding it. True/False.
​Ans:  False

Q9: What is the unit of temperature as adopted by India?
​Ans:  Degree Celsius (°C)

Q10: What is the average body temperature of a healthy person?
​Ans:  37°C

Q11: What is the range of laboratory thermometers?
​Ans:  - 10°C to 110°C

Q12: Laboratory thermometer should be kept upright and not tilted. True/False.
​Ans: True.

Q13: The bulb of the laboratory thermometer should not touch the surface of the ________________.
​Ans:  Container.

Q14: What is the use of kink in a clinical thermometer?
​Ans:  Kink prevents mercury levels from falling on their own.

Q15: Give an example to show the transfer of heat from one body to another.
​Ans:  Any utensil kept on flame becomes hot because heat transfers from flame to the utensil.

Q16: Heat always flows from a hotter object to ________________.
​Ans:  Colder object

Q17: In solid heat is transferred by the process of
​a. Conduction
b. convection
c. Radiation
d. None of these
​Ans: Conduction.  

Q18: Give examples of conductors.
​Ans:  Aluminium, copper, iron etc.

Q19: Give examples of insulators.
​Ans: Wood, plastic, rubber

Q20: Insulators are ________ conductors of heat.
​Ans: Poor

Q21: Conductors are _____________ conductors of heat.

Ans: Good

Q22: Name the process by which heat transfers in air.
​Ans: Convection.

Q23: From the sun, the heat comes to us by the process called __________________.
​Ans: Radiation.

Q24: Which of the two absorbs more radiation- a dark-coloured object or a light-coloured object?
Ans:  A dark-coloured object.

Q25: The temperature of boiling water cannot be measured by a ________________________.
​Ans:  Clinical thermometer

Q26: Land breeze blows at the time of __________.
​Ans: Night

Q27: Sea breeze blows at the time of _________.
​Ans:  Day

Q28: Which type of clothing should be preferred for the month of June?
​Ans: Light-coloured clothes

Q29: Which type of clothing should be preferred in January?
​Ans: Dark coloured clothes.

Q30: A cold steel spoon is dipped into a cup of hot coffee. Will it transfer heat to its other end or not? If yes, then by which process?
​Ans: Yes, by conduction.