Photons

Question 1

What is the wavelength formula?

Answer 1

λ = c/f

Question 2

What do electromagnetic waves consist of?

Answer 2

Electromagnetic waves consist of an electric wave and a magnetic wave which travel together and vibrate.

Question 3

What are some features of electromagnetic waves?

Answer 3

• Electric and magnetic waves vibrate and travel together at right angles to each other and to the direction in which they are travelling.
• Are in phase with each other.

Question 4

When can electromagnetic waves be emitted by a charged particle?

Answer 4

• Fast moving electron is stopped or slows down or changes direction.
• Electron in a shell of an atom moves to a different shell of a lower energy,

Question 5

How are electromagnetic waves emitted?

Answer 5

• Emitted as short bursts of waves, each burst leaving the source in a different direction.
• These are photons.

Question 6

What is the formula for the energy of a photon?

Answer 6

E = hf
E = h*c/λ

Question 7

What is a laser beam?

Answer 7

A beam which consists of photons of the same frequency.

Question 8

What is the formula for the power of a laser beam?

Answer 8

Power = nhf
n = number of photons in a beam passing a point in a second.
hf = energy.

Question 9

How does electromagnetic radiation exist?

Answer 9

Electromagnetic radiation exists of photons of energy.