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Heat
Very Short Questions
1. What
is heat?
Heat is the form of energy that gives the sensation of
warmth.
2. How
does heat move?
Heat moves by conduction, convection and radiation.
3. What
are the sources of heat?
The sources of heat are: burning coal, sun, electric
heater, etc.
4. What
is heat absorption?
Heat absorption is the process by which an object
takes in heat energy from its surrounding.
5. Which
material is a good conductor of heat out of copper wire and piece of wood?
Copper wire is a good conductor of heat out of copper
wire and piece of wood.
Short Questions
1. Define
heat and its role in energy transfer.
Heat is the form of energy that gives the sensation of
warmth. It plays important role in energy transfer by moving heat energy from a
hotter object to a colder object until both objects reach the same temperature.
2. What
are the three main methods of heat transfer?
The three main methods of heat transfer are:
i) Conduction
ii) Convection
iii) Radiation
3. How
is heat produced in everyday activities, such as cooking or using electronic
devices?
Heat is produced in everyday activities, such as cooking or using
electronic devices by the conversion of electric or chemical energy into heat
energy.
4. Not
necessary
5. Why
do dark-coloured objects heat up faster in sunlight compared to light-coloured
objects?
Dark-coloured objects absorb most of the wavelength of
light whereas light-coloured objects reflect most of the wavelength of light
including infrared radiation. So, dark-coloured objects heat up faster in
sunlight compared to light-coloured objects.
6. Explain
why metals feel colder than wooden objects at room temperature, even though
they are at the same temperature.
Metals feel colder than wood at the same temperature because metals are good
conductors of heat. They quickly take heat away from our skin, making them feel
cold, while wood is a poor conductor and does not take heat away as fast.
7. What
are the effects of absorption of heat on the surface of area of bodies?
The absorption of heat depends on the surface area of
a body. A larger surface area absorbs more heat, while a smaller surface area
absorbs less heat.
8. Two
metal plates, one white and another black are kept in sunlight for ten minutes.
Which plate will have more temperature and why?
The black metal plate will have a higher temperature
because it absorbs more heat from sunlight, while the white plate reflects most
of the light and absorbs less heat.
Long Questions
1. Name
the sources of heat energy and also mention its uses.
चित्र बनाऊ
i) Electric Heater: It is used to make the room warm.
ii) Burning firewood: It is used to cook food and provide warmth in winter
iii) Sun: It provides heat and warmth to entire planet.
2. Explain
the importance of heat in our daily life in any four points.
The four importance of heat in our daily life are:
i) Heat helps us cook food.
ii) Heat keeps our body warm.
iii) Heat helps dry clothes and grains.
iv) Heat is used to generate electricity.
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