Science Revision test questions (Heat) class 7

HEAT

1. A beggar wrapped himself with a few layers of newspaper on a cold winter night. This helped him to keep himself warm because

    a.      newspaper is at a higher temperature than the temperature of the surrounding
   b.     newspaper is conductor of heat
   c.      friction between the layers of newspaper produces heat
   d.     air trapped between the layers of newspaper is a bad conductor of heat
Ans. d.     air trapped between the layers of newspaper is a bad conductor of heat

2. Paheli and Boojho measured their body temperature. Paheli found her's to be 98.6°F and Boojho recorded 37°C. Which of the following statement is true?
    a.      Both are suffering from fever
    b.     Paheli has a higher body temperature than Boojho
    c.      Both have normal body temperature
    d.     Paheli have lower body temperature than Boojho
Ans. c.     Both have normal body temperature

3. The heat in liquids and gases is transferred by the process of
    a.      Radiation
    b.     Convection
    c.      Conduction
    d.     Absorption
Ans. b.     Convection

4. During the night
    a.      Land cools more quickly than the sea
    b.     Sea cools quickly than the land
    c.      Land heats up
    d.     Sea water heats up
Ans. a.      Land cools more quickly than the sea

5. Conduction of heat does not take place in
    a.      Copper
    b.     Iron
    c.      Silver
    d.     Wood
Ans. d.     Wood

6. Dark-coloured clothes keep the body warm because they are
    a.      good absorbers of heat
    b.     bad absorbers of heat
    c.      neither good nor bad absorbers of heat
    d.      none of these
Ans. a.      good absorbers of heat

7. Water and air are _______ conductors of heat.
Ans. poor

2.    8.  _______ is the liquid used in thermometer.

    Ans. Mercury

        9._______ is the degree of hotness of the body.

    Ans. Temperature

4 10.The range of laboratory thermometer is ______________.    

    Ans. -10˚C to 110˚C

5.   11. The ______________ in clinical thermometer prevents the back flow of mercury into the bulb.

    Ans. Kink

    12.  In places of hot climate, it is advised that the outer walls of houses be painted white. Why?

\    Ans. In places of hot climate, it is advised that the outer walls of houses be painted white because white colour is a light colour and it reflects most of heat that falls over it. Hence, helps in reducing temperature of the house.

    13.   Identify two conditions that are necessary for conduction of heat.

    Ans. i) Difference between temperatures at the both ends of the object.

            ii) The objects at temperature differences must be in contact with the each other.

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