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Why can heat only be transferred through a vacuum by radiation, and not conduction or convection? (3)

Heat transfer by conduction and convection works by particles colliding and transferring energy, as there are no particles in a vacuum heat transfer can only occur by radiation. This is because radiati...

Answered by James W. • Physics tutor

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Explain the photoelectric effect, when does it occur and what is its significance in understanding the nature of light ? (6)

metal (unlike insulators ) contains free electrons (1)

kinetic energy transferred from the light incident on the surface to the free electrons (1)

The maximum kinetic energy of the electrons...

Answered by Helena R. • Physics tutor

1597 Views

The mercury atoms in a fluorescent tube are excited and then emit photons in the ultraviolet region of the elecrtomagnetic spectrum. Explain how the mercury atoms become excited.

The mercury atom is excited one of its electrons goes from an upper electron shell to a lower electron shell thanks to some energy that it recives from the outside. When an atom is excited it is instable ...

Answered by Marie B. • Physics tutor

4145 Views