CBSE Class 7 Science Heat Worksheet Set B

Question. How do solar cells (fitted in satellites) work in space even though it is black all around?
(a) Even though it is black around, sunlight is present and charges the solar cells as on earth.
(b) There is no sunlight, but the solar cells are charged by the light from the stars.
(c) The cells are charged on Earth for life long use and do not need to be charged in space.
(d) They get charged during the day time in space, when it is not black all around.

Answer : A

Question. Mayank visited a power plant and saw this board outside. What type of plant must it have been?

(a) Thermal power plant
(b) Nuclear power plant
(c) Gas-based power plant
(d) It could have been any type of power plant.

Answer : B

Question. The picture shows the molecular arrangement of a material X. If the material is subjected to increase in temperature, what will be the likely change in its molecular arrangement?

Answer : C

Question. Nitrogen condenses at -196 deg C and freezes at -210 deg C. At which of the following temperatures can you store nitrogen in LIQUID form?
(a) -225 deg C
(b) -190 deg C
(c) -200 deg C
(d) 0 deg C

Answer : C

Question. The boiling point of water at the top of Mount Everest may be which of the following?
(a) 112deg C
(b) 100 deg C
(c) 69 deg C
(d) 0 deg C

Answer : C

Question. Which of the following could be placed in a glass tumbler before pouring hot milk into it to reduce the chances of the tumbler cracking due to the heat?

Answer : B

Question. Why is it hotter in summer than in winter?
(a) this is due to the Earth being closer to the Sun in summer.
(b) this is due to the tilt in the axis of the Earth.
(c) this is due to the rotation of the Earth on its axis.
(d) this is due to hot winds that blow on the Earth's surface.

Answer : B

Question. When solid candle wax is heated, it becomes liquid. The molecules
(a) Absorb heat and move apart.
(b) absorb heat and come together
(c) Release heat and move apart.
(d) Release heat and come together.

Answer : A

Question. What is the difference between evaporation and boiling?
(a) There is no difference - they are exactly the same.
(b) Evaporation, unlike boiling, occurs at all temperatures.
(c) In evaporation, unlike in boiling, there is no state change.
(d) In boiling, unlike in evaporation, the liquid volume reduces.

Answer : B

Question. Rahul ties a string around a stone. He takes three beakers with equal volumes of water, cooking oil and kerosene. He then immerses the stone completely in each of the 3 beakers, one after the other. What is he likely to find?

(a) The level of the liquid falls by different amounts in the three beakers.
(b) There is an unequal increase in the level of the three liquids.
(c) There is an equal increase in the level of the three liquids.
(d) The level of the liquid does not change in any of the three beakers.

Answer : C

Question. The rate of cooling of a piece of metal increases with an increase in its exposed surface area. 3 identical blocks of aluminum are used to make three different pieces. Which of these will lose heat fastest?

Answer : C

Question. Three beakers containing different liquids are placed in a room where the room temperature is about 25°C. What would be the correct set of temperatures of the three liquids?

(a) A
(b) B
(c) C
(d) D

Answer : C

Question. Which of these metals remains a liquid over the widest range of temperature?
The table below gives the melting and boiling points of a few metals. Use it to answer the question. 

(a) Silver
(b) Tin
(c) Aluminum
(d) Tungsten

Answer : D

Question. Soft solders are filler metals that melt and flow below 430°C. Which pair of metals would be most suitable for soft solders?
The table below gives the melting and boiling points of a few metals. Use it to answer the question.

(a) Silver and gold
(b) Tin and aluminum
(c) Tin and lead
(d) Aluminum and Tungsten

Answer : C

Question. Four thermometers are shown below. Which of these would be the MOST appropriate to measure our body temperature?

Answer : B

TOPIC : Heat 

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