Q1) The temperature of a body rises by 1°C. What is the corresponding rise on the
(a) fahrenheit scale
(b) kelvin scale
Q1) Write true or false for each statement
(a) on touching a lump of ice, we feel cold because some heat passes from our body to the ice.
(b) heat flows from a body at high temperature to a body at a low temperature when they are kept in contact.
(c) all solids expand by the same amount when heated to the same rise in temperature.
(d) telephone wires are kept tight between the two poles in summer.
(e) equal volumes of different liquids expand by different amounts when they are heated to the same rise in temperature.
(f) solids expand the least and gases expand the most on being heated.
(g) a mercury thermometer makes use of the property of expansion of liquids on heating.
(h) kerosene contracts on heating.
(i) water is a bad conductor of heat.
(j) medium is necessary for the transfer of heat by radiation.
(k) land and sea breezes are convection currents of cold and warm air.
(l) liquids are heated by conduction and radiation.
(m) black surfaces are the poor absorbers of heat radiations.
Q2) Fill in the blanks
(a) heat is a form of _____
(b) ______ determines the degree of hotness or coldness of a body.
(c) on heating a body, its temperature _____.
(d) we use a _______for measuring the temperature of a body.
(e) the S.I unit of temperature is _____.
(f) in a thermometer, the commonly used liquid is ______.
(g) the temperature of a normal human body is____
(h) a person is said to have fever if his body temperature is more than _____
(i) a hot metallic piece is placed in tap water contained in a bucket. Heat will flow from
___ to ______.
(j) the temperature of boiling water is _____
(k) liquids expand _____than the solids.
(l) gases expand ______than the liquids.
(m) heat transfer in solids is by _______
(n) heat transfer in liquids and gases is by ______.
(o) metals are _______of heat.
(p) still air is an insulator of heat.
(q) black and dull surfaces are___ of heat.
Q3) Match the following :
|Column A||Column B|
|(a) mercury||(i) insulator|
|(b) wood||(ii) water from 0° to 4°|
|(c) aluminum||(iii) absorbs|
|(d) contracts||(iv) conductor|
|(e) black surface||(v) thermometer|
Q4) Select the correct alternative
(a) if we add a lump of ice to a tumbler containing water
Heat flows from water to ice
heat flows from ice to water
heat flows from water to ice water is more
heat flows from ice to water if ice is more
(b) the temperature of pure melting ice is
(c) a thermometer uses
none of the above
(d) which of the statement is correct
Iron rims are cooled before they are placed on cart wheels
A glass stopper gets tight on warming the neck of the bottle
Telephone wires sag in winter, but become tight in summer
A little is left between two rails on a railway track
(e) heat in a liquid is transferred by
conduction and radiation
(f) in the process of convection, heat travels
ina ll directions
(g) the vacuum kept in between the walls of a thermos flask reduces the heat transfer by
Conduction and convection
Q9) Write down the temperature of (i) lower fixed point, and (ii) upper fixed point, on the fahrenheit scale.
Q13) The fig. Shows a glass tumbler containing hot milk which is placed in a tub of cold water. State the direction in which heat will flow.
Q21) A glass stopper stuck in the neck of a bottle can be removed by pouring hot water on the neck of the bottle. Explain why?
Q27) An empty glass bottle is fitted with a narrow tube at its mouth. The open end of the tube is kept in a beaker containing water. When the bottle is heated, bubbles of air are seen escaping into the water. Explain the reason.
Q34) Select good and bad conductors of heat from the following: Copper, mercury,wood,iron,air,saw-dust,cardboard,silver,plastic,wool.
Q39) Explain why
(a) we wear woolen clothes in winter.
(b) the water pipes are covered with cotton during very cold water.
Q48) Why do we prefer to wear white or light coloured clothes in summer and black or dark coloured clothes in winter?
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