Thermal energy IV - JSS2 Basic science Past Questions and Answers - page 1
How does heat transfer through radiation?
By electromagnetic waves
By direct contact
By convection
By absorption
What is required for radiation to occur?
Medium like air or water
Extremely low temperatures
Electromagnetic waves
None of the above
What emits radiation?
Objects above absolute zero temperature
Objects below absolute zero temperature
Only the sun
Only living organisms
What happens when radiation hits an object?
It disappears
It turns into sound
It can be absorbed, reflected, or transmitted
It causes the object to freeze
Which object emits more radiation?
A warm cup of coffee
A cold cup of coffee
A wooden table
A glass of water
How do you feel the heat from a fire when you stand near it?
By convection
By conduction
By radiation
By insulation
What type of heat transfer is experienced on a sunny day?
Convection
Conduction
Radiation
Insulation
How does radiation differ from convection and conduction in terms of heat transfer?
Radiation transfers heat through electromagnetic waves, unlike convection which requires the movement of fluid (like air or water), and conduction which occurs through direct contact between materials.
Can you give an example of how radiation is utilized in everyday life?
One example is the use of infrared radiation in remote controls to operate electronic devices. When you press a button on a remote control, it emits infrared radiation that communicates with the device, allowing you to change channels or adjust settings without needing direct line-of-sight.
Why is radiation important for the Earth's climate?
Radiation plays a crucial role in maintaining the Earth's temperature balance. For instance, the Sun emits radiation, which warms the Earth's surface. Some of this radiation is then absorbed by the Earth and re-emitted as infrared radiation. Greenhouse gases in the atmosphere trap some of this infrared radiation, preventing it from escaping into space and helping to keep the Earth warm enough to support life. However, human activities, such as burning fossil fuels, can increase the concentration of greenhouse gases, leading to an enhanced greenhouse effect and global warming.