Students can Download Science Chapter 4 Heat Questions and Answers, Notes Pdf, KSEEB Solutions for Class 7 Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.
Karnataka State Syllabus Class 7 Science Chapter 4 Heat
Class 7 Science Heat Textbook Exercise Questions and Answers
Question 1.
State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer:
Similarities:
(a) Both clinical and laboratory thermometers consist of long, narrow, uniform and glass tubes.
(b) Both contain mercury.
(c) Both have a bulb.
(d) Both have a graduation scale on the glass tube.
Differences:
| Clinical thermometer | Laboratory thermometer |
| (a) The temperature range is35°Cto 42°C. | The temperature range is-10°C to 110°C. |
| (b) It is used to measure the temperature of the human body. | It is used to measure the temperature of substances. |
| (c) The capillary tube has a kink. | The kink is not there. |
Question 2.
Give two examples each of conductors and insulators of heat
Answer:
Conductors of heat are iron and copper. Insulators that are plastic and wood.
Question 3.
Fill in the blanks:
(a) The hotness of an object is determined by its __________.
(b) The temperature of boiling water cannot be measured by a __________ thermometer.
(c) Temperature is measured in degree __________.
(d) No medium is required for the transfer of heat by the process of __________.
(e) A cold steel spoon is dipped in a cup of hot milk. Heat is transferred to its other end by the process of __________.
(f) Clothes of __________ colours absorb more heat better than clothes of light colours.
Answer:
(a) temperature
(b) clinical
(b) Celsius
(d) radiation
(e) conduction
(f) dark.
Question 4.
Match the following:
| A | B |
| (a) The land breeze blows during | (i) Summer |
| (b) Sea breeze blow’s during | (ii) Winter |
| (c) Dark-colored clothes are preferred during | (iii) Day |
| (d) Light-colored clothes are preferred during | (iv) Night |
Answer:
(a). (iv);
(b). (iii);
(c). (ii);
(d). (i).
Question 5.
Discuss why wearing more layers of clothing during winter” keeps us warmer than wearing just one thick piece of clothing.
Answer:
Wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing because air is trapped between the layers of clothes. Air being a poor conductor of heat prevents the flow of heat from our body to the surroundings. Thus, keep the body warm.
Question 6.
Look at Figure and Mark where the heat is being transferred by conduction, by convection and by radiation.
Answer:
Heat is transferred from pan to water by conduction. Heat is transferred from burner to pan is by radiation. Heat is transferred within the water by convection.
Question 7.
In places of the hot climate, it is advised that the outer walls of houses be painted white. Explain.
Answer:
Light colours are good reflectors of light. Hence, the outer walls of houses painted with white colour reflect most of the heat and thus help in keeping the house cool.
Question 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.
Question 9.
An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will
(a) How from iron ball to water.
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to the iron ball.
(d) increase the temperature of both.
Answer:
(b) not flow7 from iron ball to water or from water to iron ball.
Question 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.
Question 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 colorful.
(c) Copper is a better conductor of heat than stainless steel.
(d) Copper is easier to clean than stainless steel.
Answer:
(c) Copper is a better conductor of heat than stainless steel.