A.Tick the correct answer:- 

1.d 2.c 3.a 4.d 5.d

B.Differentiate between the following:-

1. Heat is a form of energy and Temperature is the thermal condition of a body. Unit of heat is Kcal where as unit of temperature is kelvin.

2. Clinical thermometer also called doctors thermometer used to measure temperature of sick present. Range 35°C to 42°C.

    Laboratory thermometer are used in scientific laboratory. Range -10°C to 110°C.

3. In conduction heat flows through direct conduction.

     In convection heat flows through a medium.

4. Conductors are the substances through which heat can flow easily e.g aluminium.

       Insulators are substances through which heat can not flow e.g bakelite

C.Give one word answer for each of the following:-

1. Thermometer 2.Conduction 3.Radiation 4.Conduction 5.Laboratory thermometer

D.Match column A with column B:-

1. Insulator 2. Thermometer 3. Temperature 4.Land breeze 5.Light colours.

E.Give two examples for each of the following:-

5. Clinical and laboratory 2. Frying pan, to prepare tea 3. To warm water , melting of ice 4. Solar rays, Thermos flask.

F.Give reason for each of the following:-

1 It is is shinning metal in the liquid state which responds to temperature change quickly.

2. This is because of higher temperature in the surroundings atmosphere the body leading to dehydration, increase of heart rate and loss of appetite ,therefore the working efficiency is reduced.

3. Because the particles have to rise and fall for convection to occur it can only happen in liquids and gases, where the particles are free to move.

4. The reason for this is as follows:

During the day, land becomes more heated than the sea. Air above the land becomes warm and rises up. The cool air from the sea blows towards the land to take its place. This is called sea breeze.

           At night land cools much faster than the sea. Thus sea is warmer than the land. A current of air flows from the colder land to warmersea  to take its place. This is called the land breeze.

            The land and sea breezes are the local convection currents.

5. To keep a hot substance hot and to keep a cold substance cold.

G.Write True or False:-

1. True 2.False 3.False 4.True 5.True 6.True

H.Circle the odd one out:-  

1 temperature 2. joule 3. room heater4. digital

I.Fill in the blanks:-

1 . Liquids, gases 2. conduction 3.Kelvin 4.bad 5. higher ,lower

J.Short Answer Question:-

1. Heat is a form of energy effects of heat are:

(i)change of state (ii)change of temperature (iii)change of dimension (iv)change of composition (chemical change)

2. Temperature is the thermal condition of a body. It can be measured by different thermometer

3. The SI unit of heat is joule.

4. For conduction contact is must.

    For convection a liquid or gaseous medium is required.

    For radiation no medium is required and even if it can pass through vacuum.

5. Taking the case of thermos flask there is a gap between two inner layers which prevent conduction.

    No medium in between which prevent convection.

But radiation loose can't be totally prevented.

K.Long Answer Question:-

1. Heat is a phenomenon which is generated in the form of energy by hot objects.

Heat can we transform from hotter object to colder objects.

Heat can be obtained from electric current e.g water heater ,electric iron etc.

Heat energy can be transformed in mechanical energy e.g in steam engine.

Heat plays a vital role in day to day life.

2. Boiling point----> 100°C---> 212°F--->373°K.

Freezing Water---->0°C--->32°F--->273°K.

Celsius temperature scale also called centigrade scale. In this scale 0°C is freezing point of water and 100°C for boiling point.

Fahrenheit scale, 32°F is freezing point and 212°F is boiling point of water.

Kelvin temperature scale is the basic unit of thermodynamic temperature and is mostly used by scientist in laboratories.

3. All solids with a few exception expand on heating and contract on cooling. This property of solid can vary will be shown by a simple apparatus known as Gravelsand's ring.

       It consists of a ring clamped to a stand. The ball can pass through the ring where both of them are in same temperature. If the ball is placed in the ring after heating in a flame, it no longer pass through the ring showing that the ball (solid) expands on heating.

4. During the day, land becomes more heated than the sea. Air above the land becomes warm and rises up. The cool air from the sea flows towards the land to take its place. This is called sea breeze.

          At night land cools much faster than the sea. Thus sea is warmer than the land. A current of air blows from the colder land to warmer sea to take its place. This is called land breeze.

   The land and sea breezes are the local convection currents.

5. Radiation- It is a process of heat transfer in which the heat passes directly from one body to the other without affecting the medium. This means that no medium is needed for the heat transfer by the process of radiation. for example-

1. When we sit in the sun we feel warm we cannot get heat from the sun by conduction and convection, as both need a material medium how the most of the space between the earth and the sun is vacuum there is no material medium hence we get heat from the sun through radiation.

2. When we sit near fire we feel warm. If you hold our hands below and lighted bulb, our hands will feel warm, in this case we do not get heat by conduction. As air is a bad conductor of heat we do not get heat by convection as hot air always rises up, it does not move down words or sideways.

            This indicates that we get the heat from fire or lighted bulbs through radiation.

Characteristics of radiations are:

1.radiation does not need any material medium. It does not need molecular motion.

2. It can pass through vacuum.

6. Thermos flask is used to keep the hot or cold things for a longer period. The thermos is also known as vacuum flask. Its body is made of in such a way that it reduces three mode of loss of heat namely  conduction, convection or radiation.

      The vacuum between double walled glass surface reduces, conduction and convection as there is no medium. The silver coating on the inner bottle prevents heat transfer by radiation.