Waves

Question 1

Define reflection

Answer 1

When a wave changes direction at a boundary in the same medium

Question 2

Define refraction

Answer 2

change of speed/ direction due to change of medium

Question 3

Define diffraction

Answer 3

spreading out of a wave after passing a gap (max diffraction when size of gap= wavelength)

Question 4

Explain what is meant by the principle of superposition (2 marks)

Answer 4

when two waves superpose the resultant displacement is the sum of displacements

Question 5

What is snells law

Answer 5

n1 sin i = n2 sin r

Question 6

what is the critical angle?

Answer 6

angle of incidence such that the angle of refraction is 90

Question 7

when does total internal reflection happen

Answer 7

when the angle of incidence is greater the the critical angle

Question 8

what does coherent mean?

Answer 8

same wavelength
same frequency
fixed phase difference

Question 9

equation for wavelength using Youngs double slit experiment

Answer 9

wavelength = ax/D

Question 10

what is a stationary wave

Answer 10

formed when two coherent waves travelling towards each other superpose

Question 11

Intensity=?

Answer 11

I=P/A (power, area)

Question 12

intensity is proportional to…..

Answer 12

Intensity is directionally proportional to amplitude^2

Question 13

what is a materials refractive index?

Answer 13

ratio between the speed of light and the speed of light through the material

Question 14

what are the two conditions for total internal reflection?

Answer 14

when light travels from medium with higher refractive index to lower
angle of incidence is greater than C