Heat

Q. The normal temperature of a human body is ___ degree Celsius.

Q.

The best and the poorest conductors of heat are respectively

1. copper (Cu) and aluminium (Al).

2. copper (cu) and gold (Au)

3. silver (Ag) and gold (Au)

4. silver (Ag) and lead (Pb).

Q.

State the precautions of using laboratory thermometer.

Q.

Why does the bottom of a lake not freeze in severe winter even when the surface is all frozen?

1. Conductivity of ice is high.

2. Water has large specific heat.

3. Conductivity of ice is low.

4. Temperature of the earth at the bottom of the lake is high.

Q. What is the difference between thermal energy and heat energy?

Q. Energy can neither be created nor destroyed i.e. the total energy of the universe remains constant; however, it transforms from one form to another. The same phenomena apply when we burn a candle, chemical energy of wax is converted to light energy and heat energy.

1. True
2. False

Q.

What are good conductors of heat? Give examples.

Q. An iron ball at ${40}^{\circ }C$ is dropped in a mug containing water at ${40}^{\circ }C$. Which of the following is correct?

1. Temperature of both will increase.
2. Heat will flow from iron ball to water.
3. Heat will flow from water to iron ball.
4. There will be no heat flow.

Q. "Take a beaker containing cold water and another one containing hot water. Put a drop of ink to each of them". Which of the option is/are related to the above statement.

1. In the beaker containing cold water, ink spreads slowly.
2. In the beaker containing hot water, ink spreads faster.
3. The spreading of ink takes place due to the movement of water molecules.
4. Ink will not dissolve.

Q.

Question 8
One liter of water at ${30}^{\circ }C$ is mixed with one liter of water at ${50}^{\circ }C$. The temperature of the mixture will be

(a)${80}^{\circ }C$
(b) more than ${50}^{\circ }C$ but less than ${80}^{\circ }C$
(c) ${20}^{\circ }C$
(d) between ${30}^{\circ }C$ and ${50}^{\circ }C$

Q. The energy transferred from one body to another without any work involved is called .

1. Heat
2. Temperature
3. Coldness
4. Kinetic energy

Q. What is the principle of working of a thermometer?

1. Thermal expansion of solids
2. Thermal expansion of gases
3. Thermal expansion of liquids
4. All of the above.

Q.

What precautions will you take while measuring temperature with a laboratory thermometer? What extra precaution will you take while measuring body temperature with a clinical thermometer?

Q.

Which element(s) is/are used in the manufacturing of solar cells?

1. silicon

2. Silver

3. Gold

4. Zinc

Q.

The thermometer used to measure the human body temperature is called the ______________ thermometer.

Q. A dark funnel shaped cloud that reaches from the sky to the ground is called a

1. hurricane
2. tornado
3. thunderstorm
4. typhoon

Q. Which of the following will radiate heat to a large extent?

1. Rough surface
2. Polished surface
3. Black rough surface
4. Black polished surface

Q. Which of the following precautions we must take during thunderstorm?

1. Take shelter under a tall tree.
2. Stay inside the house.
3. Get out of the water.
4. Take shelter inside a car.

Q.

Cooking utensils are provided with handles made of plastic. Why?

Q. Two blankets makes us feel warm than one, because__________.

1. two blankets help us loose more heat
2. air is trapped between the blankets
3. heat does not reach us from the surroundings
4. blankets are a good conductor of heat

Q.

In radiation, the transfer of heat takes place with the help of a medium.

1. True
2. False

Q.

Define thermometer.

Q.

Can Heat be Converted to Work?

Q.

When does a wind blow ?

1. During earthquake.

2. When there is no change in temperature betwen the regions.

3. When there is a pressure difference between the regions.

4. When there is no pressure difference between the region.

Q.

Which among the following is not an effect of heat energy being imparted to a body?

1. change in temperature.

2. Change of mass of the body

3. Change in dimension and state of matter.

4. Chemical changes.

Q.

Explain briefly the process of heat transfer by radiation.

Q. The pressure exerted by the atmosphere on us is called _________.

1. ground pressure
2. atmospheric pressure
3. ecological pressure
4. hydraulic pressure

Q.

The direction of heat transfer depends on which of the following?

1. Temperature of each body.

2. Shape and size of the body.

3. Mass of each body.

4. Amount of heat contained in each body.

Q.

Liquids and gases are good conductors of heat.

1. True
2. False

Q.

Question 9
An iron ball at ${40}^{\circ }C$ is dropped in a mug containing water at ${40}^{\circ }C$. 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.