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31. Which among the following denotes the smallest temperature?
A. 1 0C on the fahrenheit scale
B. 1 0C on the fahrenheit scale
C. 1 0C on the kelvin scale
D. 1 0c on the Celsius scale
ANSWER:C
SOLUTION :1° on the Kelvin scale denotes the smallest temperature.
32. Heat transfer horizontally within the atmosphere is called ?
A. Conduction
B. Convection
C. Radiation
D. None
ANSWER:D
SOLUTION:The transfer of heat through the horizontal movement of air is called advection.
33. When ice is heated from 0 0C to 10 0C, the volume of water ?
A. First decreases then increases
B. First increases then decreases
C. Increases steadily
D. Decreases steadily
ANSWER:A
SOLUTION:when water is heated from 0oC to 10oC, its volume first decreases and then increases.
34. Why can two thin shirts keep us warmer than one thick shirt in winter ?
A. Heat does not radiate
B. The air layer between the two shirts acts as an anti – medium
C. Air layer acts as an conductor between two shirts
D. None
ANSWER:B
SOLUTION:We wear more layers of clothing during winter to keeps us warmer than wearing just one thick piece of clothing because air gets trapped in between the two layers of blankets.
35. In the summer season, fan air makes us feel good because?
A. The fan will cool the wind
B. Our sweat evaporates rapidly
C. Conductivity of air increases
D. None
ANSWER:B
SOLUTION:A fan produces a feeling of comfort because our perspiration or sweating evaporates rapidly. Our body try to cool ourselves releasing sweat through pores of skin. And when we sit under the fan the sweat evaporates due to directed air upon us making our body cool as evaporation is the cooling process.
36. When a piece of ice floating in a glass of water melts, the water level?
A. Will rise
B. Will fall down
C. Will remain the same
D. None
ANSWER:C
SOLUTION :When an ice cube floating in a glass of water melts, the water level in the glass remains the same. This is because the ice displaces an amount of water equal to its volume and when it melts, it occupies the same volume in the water.
37. The main use of sweat is?
A. In controlling body temperature
B. In keeping the amount of water in the body balanced
C. Extracting toxins in the body
D. None
ANSWER:A
SOLUTION:Its main function is to control body temperature. As the water in the sweat evaporates, the surface of the skin cools. An additional function of sweat is to help with gripping, by slightly moistening the palms.
38. Hand pump water is hot in winter because?
A. Friction creates friction due to which the water is heated
B. Our body is cold during winters, so water looks hot
C. Both A & B
D. None
ANSWER:B
SOLUTION: our body is cold in winter and water appears to be warm. the pumping process causes friction which warms up the water. the temperature inside the earth is higher than the atmospheric temperature. inside water comes out and absorbs heat from the environment.
39. An electric heater kept in vacuum, is heated continuously?
A. Will stop rising after some time
B. Will go on rising with time
C. Will become constant after some time because of loss of heat
D. None
ANSWER:C
SOLUTION: An electric heater kept in vacuum is heated continuously by passing an electric current. Its temperature. will go rising with the time. will stop rising after sometime as it will lose heat to the surroundings by conduction.
40. Metal tea pot have wooden handles because?
A. It prevents electric shock
B. It gives beauty to the pots
C. Wood is bad conductor of heat
D. None
ANSWER:C
SOLUTION:Metal tea pots have wooden handles because wood is a poor conductor of heat, preventing the heat from the pot from transferring to your hand. This allows you to hold the pot comfortably, even if it’s hot.