worksheet -HEAT ( 15-5-20)

Good morning boys.Thank you for logging in.

Today we shall be doing a revision worksheet on the chapter HEAT.

You will be able to:

• recall facts and concepts to complete today's work
• revise the chapter
• 
  

LET US BEGIN:

DO THE WORKSHEET IN YOUR SCIENCE NOTEBOOK

Q.1 Fill in the blanks:

1. Heat transferred by radiation is called_____________radiation.
2. The degree of hotness or coldness of a body is called____________.
3. The three modes of heat transfer are______ ,_____________ and ______________.
4. _______________ and _________________ are poor conductors of heat.
5. Convection current from land to sea is called ___________________breeze.
6. Only ___________ and _____________ transfer heat by convection.
7. For conduction of heat to occur ,the two objects should be at___________temperatures.
8. 1 kilocalorie = ___________calories.

Q.2 Define the following terms:

a]conduction

b] heat

c] insulator

Q.3 Distinguish between:

1. Convection and radiation as methods of heat transfer
2. Clinical and lab thermometers

Q.4 Name the method of heat transfer in each of the following:

a) a  spoon kept in a hot cup becomes warm

b) heat energy reaching us from the sun

c) a bowl of water heated on a gas stove become warm

Q.5 Choose the correct option:

1. Which one is a good conductor of heat:

a) wood

b) straw

c) rubber

d) copper

2. Which one of these is a bad conductor of heat:

a) Wood

b) gold

c) copper

3. The range of a clinical thermometer is:

a) 37-43 C

b) 35-42 C

c) 39-45  C

4.  Which one is used as a thermometric liquid:

a) water

b) mercury

c) bromine

Q.6 Answer the following briefly:

a) State two precautions to be taken while using a clinical thermometer.

b) Why can you not keep your hand above a burning candle but can do so on the sides of the flame?

c) At a campus site, there are tents of two shapes one made with black fabric and the other made with white fabric, Which one will you prefer for resting in on a hot summer afternoon and why?

d] Why does a clinical thermometer have a kink?

 Q 7. Look at the diagram given below. Write the method of heat             transfer in [1], [2] and [3].

CHECK YOUR ANSWERS NOW:

Q.1 Fill in the blanks:

1. thermal
2. temperature
3. conduction, convection and radiation
4. wood, plastic
5. land breeze
6. gases , liquids
7. different
8. 1000

Q.2 Define

Conduction: Mode of heat transfer in which heat passes from the  hotter to colder parts or from a hotter to colder body in contact with it.

Heat: It is a form of heat energy which causes the sensation of hotness or coldness.

Insulator: Materials that do not conduct heat and electricity.

Q.3 Distinguish:
1] convection: needs a medium, takes place in liquids and gases, is a slow process
    radiation: no medium needed, can occur through empty space, propogates at the speed of light.

2] clinical: capillary with a kink, reading is taken by removing away from the body.
    lab: straight capillary, reading taken when bulb is in contact with substance.

Q.4 Name the method of heat transfer:

    

1. conduction
2. radiation
3. convection

Q.5 Choose the correct option:

1. copper 
2. wood 
3. 35 to 42 C
4. mercury

Q. 6 Answer briefly:

a] Wash the thermometer with antiseptic solution before and after use.
Never hold the thermometer by the bulb when reading the temperature.

b] Hot air from the flame will move upwards, not sideways. Our hand will get burnt above the flame.

c] The tent made of white fabric is preferable because it will absorb less heat and remain cool.

d] It has a kink to prevent the mercury from falling back into the bulb.

Q. 7 Name the method of heat transfer:

1. convection
2. conduction
3. radiation

That is all for today

See you soon!