Black body radiation

The photograph shows a camper van with a solar panel on its roof. The solar panel is made from lots of solar cells connected together.

The solar panel is connected to a battery. The solar panel receives energy from the Sun to charge the battery.

Describe how energy is transferred from the Sun’s energy store to the battery’s energy store.

The petrol engine can also be used to charge the battery of the camper van.

Give an advantage of using the solar panel instead of the petrol engine to charge the battery.

Do not refer to cost in your answer.

The surface of the solar panel is black.

Explain why black is a suitable colour for the solar panel.

The solar panel can charge the battery in the camper van with a maximum current of 15 A.

Calculate the minimum time to transfer 360 000 C of charge through the battery.

Use the formula

charge transferred = current × time

This question is about the Sun.

The table shows the different stages in the evolution of stars of different masses.

Complete the table by adding ticks () to show which stages of evolution occur in the life cycle of the Sun.

When viewed from Earth, the surface of the Sun is yellow in colour.

The surface of another star, Betelgeuse, is red in colour.

Explain the difference between the Sun and Betelgeuse, based on the different colours of their surfaces.

The Sun transfers energy to the Earth by radiation.

Give a reason why energy is not transferred from the Sun to the Earth by conduction or convection.

A satellite orbiting the Earth contains sensitive equipment that can be damaged if it gets too hot.

Explain which colour would be most appropriate for the outer surface of the satellite to protect the equipment.

Table 1 shows the colour of some stars.

Complete table 2 by giving the stars in order of increasing surface temperature.

The hottest star, Rigel, has been done for you.

A star has a much larger mass than the Sun.

Describe the evolution of this star after it has left the main sequence.

The graph shows the relationship between the peak wavelength of light emitted by a star and the surface temperature of the star.

A scientist suggests that the two variables are linked by this formula.

peak wavelengthsurface temperature = constant

Use data from the graph to justify this formula.

The diagram shows a building in a hot climate.

The air temperature is 35 °C and the underground temperature is 12 °C.

The external pipe is heated by the Sun. This causes cool air to enter the house through a tube in the ground.

How is energy transferred to the external pipe from the Sun?

Explain why air moves upwards through the external pipe.

Warm air enters the tube at point X.

Cool air leaves the tube at point Y.

Explain how the air is cooled as it travels through the tube.

The external pipe is painted to increase the air flow through the building.

Explain what colour of paint would give the greatest increase in air flow.

The diagram shows the apparatus used to demonstrate the existence of electromagnetic radiation just beyond the visible spectrum.

Electromagnetic radiation from the Sun passes through a slit and a prism.

The electromagnetic radiation refracts through the prism onto the screen.

Five thermometers are placed in front of the screen.

Complete the table to show the missing parts of the electromagnetic spectrum.

Suggest why the lower part of each thermometer should be painted black.

The equipment is left for a short period of time.

The thermometers now show higher temperatures than before.

State the part of the electromagnetic spectrum in this demonstration that would give the largest temperature increase.

The photograph shows a large hurdle on an athletics track.

The bar of the hurdle is made of wood and is painted black and white.

The temperature of the hurdle increases when the Sun shines on it.

Explain which part of the bar reaches the highest temperature.

The air near the bar receives energy by heating.

Explain how a convection current is formed in the air near the bar.

The photographs show two different breeds of cat.

Cat X has no fur and light-coloured skin.

Cat Y has thick, black fur.

Both cats have the same body temperature and transfer energy to their surroundings when they are outside on a cold day.

Compare how cat X and cat Y transfer energy to their surroundings.

Refer to conduction, convection and radiation in your answer.