Science - Heat
Exam Duration: 45 Mins Total Questions : 30
Which of the following conditions enables heat to flow from one body to another identical body?
- (a)
The difference in the temperatures of the two bodies
- (b)
The difference in the pressures exerted on the two bodies
- (c)
The difference in the densities of the two bodies
- (d)
The difference in the sizes of the two bodies
When you heat water in a pot, it boils. What can you infer from the above observation?
- (a)
Heat is a form of energy.
- (b)
Water can boil by itself.
- (c)
Water develops heat on its own.
- (d)
Water is a universal solvent
What must be done to enable mercury in a glass thermometer to respond quickly to changes in temperature?
- (a)
The bore should be narrow.
- (b)
The wall of stem should be thin.
- (c)
The bulb should contain a lot of mercury.
- (d)
The wall of glass bulb should be thin.
Why do cooking vessels usually have copper bottoms?
- (a)
Copper has low melting point.
- (b)
Copper is an insulator of heat.
- (c)
Copper is a good conductor of heat.
- (d)
Copper is cheap.
What is the measure of the degree of hotness or coldness of a body called?
- (a)
Heat energy
- (b)
Celsius
- (c)
Kelvin
- (d)
Temperature
Why are two thin blankets piled together warmer than a single one of the same total thickness as the two?
- (a)
Air is enclosed in between them.
- (b)
The outer thin blanket transfers heat faster.
- (c)
Air acts as medium to transfer the energy.
- (d)
There is a decrease in the sensation of touch.
Why is it hotter over the top of a fire than at the same distance on the sides?
- (a)
Due to convection of heat
- (b)
Due to conduction of heat
- (c)
Due to radiation of heat
- (d)
Due to conduction, convection and radiation of heat
Which of the following is NOT a scale of temperature?
- (a)
Kelvin scale
- (b)
Celsius scale
- (c)
Fahrenheit scale
- (d)
Richter scale
How many parts does a Celsius scale have?
- (a)
100
- (b)
273
- (c)
180
- (d)
50
What is the range of a clinical thermometer?
- (a)
0-100 °C
- (b)
32-214 °F
- (c)
0-273°C
- (d)
35-42°C
Identify the normal human body temperature.
- (a)
32 °F
- (b)
212 °F
- (c)
100.4 °F
- (d)
98.4 °F
By which mode of transmission of heat does air get heated up?
- (a)
Conduction
- (b)
Convection
- (c)
Radiation
- (d)
Diffusion
In cold countries, why are steam pipes covered with asbestos or glass wool?
- (a)
To prevent bursting due to expansion
- (b)
To prevent heat loss due to conduction
- (c)
To prevent radiation
- (d)
All of the above
Windows having double glass panes with some space between them is called double glazing. Why do windows in cold countries have double glazing?
- (a)
For the conduction of heat
- (b)
For the insulation of heat
- (c)
For the radiation of heat
- (d)
All of the above
Which of the following is a good conductor of heat?
- (a)
Plastic
- (b)
Water
- (c)
Glass
- (d)
Copper
What is the mode by which heat is transferred in solid substances?
- (a)
Conduction
- (b)
Convection
- (c)
Radiation
- (d)
Insulation
Which of the following is a bad conductor of heat?
- (a)
Wood
- (b)
Aluminium
- (c)
Iron
- (d)
Bronze
Which is the best conductor of heat?
- (a)
Silver
- (b)
Iron
- (c)
Aluminium
- (d)
Copper
Why are tea cups never made of metals?
- (a)
Metals are good conductors of heat.
- (b)
Metals are lustrous.
- (c)
Metals are expensive.
- (d)
Metals have high melting point
In which of the following is the rate of heat transfer more?
- (a)
Glass
- (b)
Copper
- (c)
Plastic
- (d)
Wood
Rooms are fitted with ventilators to let hot air out. What is the phenomenon involved in the above?
- (a)
Conduction
- (b)
Convection
- (c)
Radiation
- (d)
Condensation
What enables birds to glide effortlessly in the air?
- (a)
Conduction of heat in the air
- (b)
Radiation through the atmosphere
- (c)
Convection currents of air
- (d)
More sugar in their body cells
When we touch a steel rod and a sheet of paper simultaneously, why do we feel that the steel rod is colder than the sheet of paper?
- (a)
Steel, being a good conductor, absorbs heat from our body.
- (b)
Paper being a good conductor, absorbs more heat from our body.
- (c)
Heat flows from steel to our body.
- (d)
Heat flows from the paper to our body
What is the energy conversion taking place in an electric heater?
- (a)
Chemical energy is converted to electrical energy.
- (b)
Electrical energy is converted to chemical energy.
- (c)
Heat energy is converted to electrical energy.
- (d)
Electrical energy is converted to heat energy.
Which of the following statements is true about convection?
- (a)
In solids, heat is transferred only by convection.
- (b)
Convection occurs in cold liquids.
- (c)
Convection requires a medium for transmission.
- (d)
Heat flows from the cold end to the hot end in a substance.
Riaz needs a box which can absorb the heat from the sun very fast but lose it very slowly. How should the outer and the inner surface of the box be coloured so that he gets the best result?
- (a)
Outer - Silver, Inner - Silver
- (b)
Outer - Black, Inner - Black
- (c)
Outer - Silver, Inner - Black
- (d)
Outer - Black, Inner - Silver
Which part of a thermos flask prevents loss of heat through radiation?
- (a)
Vacuum
- (b)
Cork stopper
- (c)
Double glass walls
- (d)
Shiny, silvery wall
What happens when the temperature of a substance is increased?
- (a)
Kinetic energy of the molecules of the substance increases.
- (b)
Kinetic energy of the molecules of the substance decreases.
- (c)
The amplitude of vibrations of molecules of the substance about their mean position decreases.
- (d)
It does not cause any change.
Why do solar panels have black surfaces?
- (a)
Because they are good absorbers of heat
- (b)
Because they are bad absorbers of heat
- (c)
Because they are good reflectors of heat
- (d)
Because they are bad radiators of heat
The base of a cooking vessel is usually black and dull. Why is it made this way?
- (a)
Black is a favourite colour of most of the consumers.
- (b)
Dull surfaces prevent slipping of vessels.
- (c)
Black and dull surfaces are good absorbers of heat.
- (d)
Black and dull surfaces are good reflectors of heat.