NCERT Solutions Class 7th Science Chapter – 3 Heat Question & Answer

NCERT Solutions Class 7th Science Chapter – 3 Heat

TextbookNCERT
Class  7th
Subject Science
Chapter3th
Chapter NameHeat
CategoryClass 7th Science
Medium English
SourceLast Doubt
NCERT Solutions Class 7th Science Chapter – 3 Heat Question & Answer How is heat produced?, What is heat in thermodynamics?, Is heat a form of energy?, What is unit of heat formula?, What are the 3 formulas of heat?, How do you measure heat?, What is the uses of heat?, What are 10 uses of heat?, How is heat transfer?

NCERT Solutions Class 7th Science Chapter – 3 Heat

Chapter – 3

Heat

Question & Answer

Q. 1. State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer – Similarities
  • Both are made of glass and consist of long narrow glass tube.
  • At one end both of them have a bulb.
  • Bulbs of both the thermometers consist of mercury
  • Celsius scale is present in both the thermometer

Differences

Clinical ThermometerLaboratory thermometer
Temperature range if 35 to 42 0 cTemperature range is -10 to 110 0 c
Used to measure human body temperatureUsed to measure temperature in the laboratory
It has kink which prevents immediate backflow of mercuryIt does not have a kink
Q. 2. Give two examples each of conductors and insulators of heat.
Answer – Conductors – aluminium, iron Insulators – plastic, wood.
Q. 3. Fill in the blanks
(a) The hotness of an object is detetmined by its ____________ .
(b) Temperature of boiling water cannot be measured by a ____________ thermometer.
(c) Temperature is measured in degree ____________ .
(d) No medium is required for transfer of heat by the process of ____________.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ____________
(f) Clothes of ___________ colours absorb heat better than clothes of light colours.
Answer – (a) temperature (b) clinical (c) Celsius (d) radiation (e) conduction (f) dark
Q. 4. Match the following:
(1) Land breeze blows during(a) summer
(ii) Sea breeze blows during(b) winter
(iii) Dark coloured clothes are preferred during(c) day
(iv) Light coloured clothes are preferred during(d) night

Answer –

(1) Land breeze blows during(d) night
(ii) Sea breeze blows during(c) day
(iii) Dark coloured clothes are preferred during(a) winter
(iv) Light coloured clothes are preferred during(b) summer
Q. 5. Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing?
Answer – More layers of clothing keep us warm in winters as they have a lot of space between them. This space gets filled up with air. Air is a bad conductor, it does not allow the body heat to escape out.
Q. 6. Look at Fig. 3.13. Mark where the heat is being transferred by conduction, by convection and by radiation
Answer –
Q. 7. In places of hot climate it is advised that the outer walls of houses be painted white. Explain.
Answer – In places of hot climate, it is advised that the outer walls of houses be painted white because white colour reflects back most of the heat that is incident on it as white is a poor absorber of heat. This helps in keeping the house cool.
Q. 8. One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will be:
(a) 80°C
(b) More than 50°C but less than 80°C
(c) 20°C
(d) Between 30°C and 50°C
Answer – (d) Between 30°C and 50°C.
Q. 9. An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will:
(a) flow from iron ball to water.
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to iron ball.
(d) increase the temperature of both.
Answer – (b) not flow from iron ball to water or from water to iron ball
Q. 10. A wooden spoon is dipped in a cup of ice-cream. Its other end:
(a) becomes cold by the process of conduction
(b) becomes cold by the process of convection
(c) becomes cold by the process of radiation
(d) does not become cold
Answer – (d) does not become cold.
Q. 11. Stainless steel pans are usually provided with copper bottoms. The reason for this could be that:
(a) copper bottom makes the pan more durable
(b) such pans appear colourful
(c) copper is a better conductor of heat than the stainless steel
(d) copper is easier to clean than the stainless steel
Answer – (c) copper is better conductor of heat than the stainless steel
NCERT Solution Class 7th Science All Chapters Question Answer
Chapter – 1 Nutrition in Plants
Chapter – 2 Nutrition in Animals
Chapter – 3 Heat
Chapter – 4 Acids, Bases and Salts
Chapter – 5 Physical and Chemical Changes
Chapter – 6 Respiration in Organisms
Chapter – 7 Transportation in Animals and Plants
Chapter – 8 Reproduction in Plants
Chapter – 9 Motion and Time
Chapter – 10 Electric Current and Its Effects
Chapter – 11 Light
Chapter – 12 Forests: Our Lifelin
Chapter – 13 Wastewater Story
NCERT Solution Class 7th Science All Chapters Notes
Chapter – 1 Nutrition in Plants
Chapter – 2 Nutrition in Animals
Chapter – 3 Heat
Chapter – 4 Acids, Bases and Salts
Chapter – 5 Physical and Chemical Changes
Chapter – 6 Respiration in Organisms
Chapter – 7 Transportation in Animals and Plants
Chapter – 8 Reproduction in Plants
Chapter – 9 Motion and Time
Chapter – 10 Electric Current and Its Effects
Chapter – 11 Light
Chapter – 12 Forests: Our Lifeline
Chapter – 13 Wastewater Story

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