1) Therm is the unit of.
Ans) Heat
2) Ice is packed in sawdust because
Ans) Sawdust is a poor conductor of heat
3) Water is used in hot water bags because
Ans) The water has high specific heat
4) A body absorbs the maximum amount of heat when
Ans) Black and rough
5) In winter season water coming out of handpump is hot because
Ans) Inside the earth the temperature is more than the atmosphere temperature
6) Due to the horizontal motion of air, transfer of heat is known as
Ans) Advection
7) Burns caused by steam is more irritation than those caused by boiling water because
Ans) Steam has more heat energy in the form of Latent heat of vaporization
8) Convection occurs in which of the following
Ans) Only liquid and gases
9) The hottest part of the gas flame is known as
Ans) Non-luminous zone
10) Earth is a
Ans) Bad absorber and a bad radiator of heat
11) Why the handles of metallic teapots made of wood
Ans) Wood is the bad conductor of heat
12) Why two thin shirts can keep us warmer than a single thick shirt in winters
Ans) Air trapped between two shirts act as an insulator and does not let body heat to travel out
13) Energy travels from sun to earth by which of the method
Ans) Radiation
14) Which is the good conductor of heat but bad conductor of electricity
Ans) Mica
15) Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in
Ans) convection
16) Device can be used to detect radiant heat
Ans) Thermopile
17) Why white clothes keep you coooler as compared to black clothes
Ans) White clothes reflect the whole light and do not absorb any heat radiation
18) When hot liquid is poured into a thick glass tumbler it cracks because of glass
Ans) Glass is a bad conductor of heat so only inner surface expands
19) A real gas can act as ideal gas at
Ans) Low pressure and High temperature
20) A white and smooth surface is
Ans) Bad absorber and Good reflector of heat
21) A black body can absorb radiations of
Ans) All wavelengths
22) In a refrigerator,, a cooling system should always be
Ans) At the top ( air on warming up rises up. This air is trapped by cooling unit on the upward side and made cool)
23) In a refrigerator what produces cooling
Ans) The sudden expansion of a compressed gas
24) The SI unit of temperature
Ans) Kelvin
25) When temperature difference between liquid and its surroundings is doubled the rate of loss of heat will
Ans) Double
26) Temperature of distant luminous bodies can be determined by
Ans) Pyrometers
27) O kelvin is equivalent to
Ans) -273 C
28) The minimum temperature is measured by
Ans) Alcohol thermometer
29) To produce the low temperature which of the following principle is used
Ans) Adiabatic demagnetization process
30) Gas thermometers are more sensitive than the liquid thermometer because the gases
Ans) Have the larger coefficient of expansion
31) Which of the following instruments is used to measure humidity
Ans) Sling Psychrometer
32) What is the triple point of water
Ans) 273.16 K
33) Why the boiling point of water decrease with increase in altitude
Ans) With increase in altitude atmospheric pressure decrease so the boiling point decrease. As boiling point is directly proportional ot the pressure
34) In extreme cold condition in cold countries water pipe get busted
Ans) On freezing water expands
35) Pressure cooker cooks faster because
Ans) Boiling point increase with an increase in pressure
36) Water is not vaporized if
Ans) Humidity is 100%
37) When heated from 0 degree C to 100 degrees C volume of a given mass of water will
Ans) First Decrease and then increase
38) Vegetables are cooked in lesser time by adding a pinch of salt while cooking because
Ans) Adding salt raises the boiling point of water
39) When water freezes its density
Ans) Decrease
40) Supecooling stands for cooling of a liquid
Ans) Below freezing point
41) Cryogenic science is related to
Ans) Low Temperature
42) What determines the colour of a star
Ans) Temperature
43) A copper disc has a hole. If the disc is heated the size of hole
Ans) Increase (metal expands on heating)
44) During hot weather the fan produces a feeling of comfort this is because.
Ans) Our perspiration evaporates rapidly
45) Conversion of heat energy into electric energy is achieved by using
Ans) Thermocouple
46) Cloudy nights are warmer because clouds mainly
Ans) Reflect back the heat given by the Earth
47) The word insolation means
Ans) Incoming solar radiation
48) The cooling by a desert cooler is based on
Ans) Evaporative cooling
49) In a diesel engine the high temperature needed to ignite the fuel is achieved by
Ans) Compressing air in the cylinder
50) Relative humidity is expressed in terms of
Ans) Percentage
