1) State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer:
Similarities
i. Both laboratory thermometer and clinical thermometer have long, narrow and uniform glass tube.
ii. Both the thermometers have a bulb which contain mercury.
Give two examples each of conductors and insulators of heat.
• i) Example of conductors are iron and copper.
• ii) Example of insulators are pure water and plastic.
Fill in the blanks:
a) The hotness of an object is determined by it’s temperature.
b) Temperature of boiling water can not be measured by a clinical thermometer.
c) Temperature is measured in degree celsius.
d) No medium is required for transfer of heat by the process of radiation.
e) A cold Steel spoon is dipped in a cup of hot milk. Heat is transferred to its other end by the process of conduction.
f) Clothes of dark colours absorb more heat better than clothes of light colours.
3) Match the following:
4) Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.
Answer:
• During winter, we wearing more layers of clothing than wearing just one thick piece of clothing because air gets trapped in between the wool fibres or between the several clothing layers.
• Air is a poor conductor of heat which prevents the flow of heat from our body to the cold surroundings, so, we feel warm.
• Hence, more layers of clothing keeps us warmer than wearing just one thick piece of clothing.
5) In places of hot climate it is advised that the outer walls of houses be painted white. Explain.
Answer:
In place of hot climate, it is advised that the outer walls of houses be painted white because white colour is a light colour having a property to reflect back most of the heat fall on it. Therefore, white colour and other light colours keep the house cool.
6) 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) The temperature of the mixture will be between 30°C and 50°C.
7) An iron 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) As both the substances have same temperature, the heat will not flow from iron ball to water or from water to iron ball.
8) 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) as wood is a bad conductor of electricity it’s other end does not become cold.
9) 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) The reason for this could be that copper is a better conductor of heat than the stainless steel.
Apex Class 
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