Light

Question 1

How fast does light travel

Answer 1

300,000 km/s

Question 2

Wavelength speed frequency

Answer 2

Speed = frequency x wavelength

m/s = F x lamda

Question 3

What do waves transfer

Answer 3

Energy and information

Question 4

Formula for sine critical angle

Answer 4

Sine critical = 1/refractive index

SinC = 1/n

Question 5

Formula for the refractive index

Answer 5

Refractive index = speed of light 1 / speed of light 2

N = sin(i) / sin(r)

Question 6

Explain how a light ray can be turned through 90 degrees using a prism

Answer 6

• incident ray is perpendicular to the surface so it is not refracted
• angle of incidence at sloping face is greater than the critical angle so total internal reflection occurs
• The reflected ray is perpendicular to the bottom surface so it isn’t refracted

Question 7

What is the critical angle

Answer 7

The critical angle is where the refracted light just runs along the boundary between the block and the air