Waves

Question 1

What is a Progressive Wave?

Answer 1

It is a wave that transfers energy in the direction of travel.

Question 2

What is Polarisation?

Answer 2

When a wave oscillates in only one direction perpendicular to the plane of movement.

Question 3

How is a stationary wave formed?

Answer 3

• Consists of antinodes and nodes
• Formed by two identical waves which are travelling in opposite directions.
• They interfere, superposing each other.

Question 4

What is an antinode?

Answer 4

Area of destructive interference.

Question 5

What is a node?

Answer 5

Area of constructive interference.

Question 6

What is superposition?

Answer 6

When two or more waves cross a point, the resultant displacement is the sum of the displacement of the waves at that point.

Question 7

What happens to the wave when it is diffracted?

Answer 7

• Direction of wave changes
• Wavelength, frequency, and time period do not change.

Question 8

Conditions to be in phase?

Answer 8

n*Lambda

Question 9

Conditions to be anti-phase?

Answer 9

(n+1/2)*Lambda

Question 10

What are coherent waves?

Answer 10

Frequency/wavelength is the same with constant phase difference.

Question 11

Why does light slow down in change of medium?

Answer 11

High density objects will refract/slow down light.

Question 12

What are the wavelengths of colour?

Answer 12

V - 400nm
I - 425nm
B - 470nm
G - 550nm
Y - 600nm
O - 630nm
R - 665nm

Question 13

What are the wavelengths for EM radiation?

Answer 13

Radio - < 10^-3
Microwave - 10^-3 to 10^-6
Infrared - 10^-6 to 7x10^-7
Visible - 7x10^-7 to 4x10^-7
Ultraviolet - 4x10^-7 - 10^-9
X - ray - 10^-9 - 10^-12
Gamma - >10^-12

Question 14

What is the equation for phase difference?

Answer 14

((difference in time for same distance) x 360 or 2pi) / wavelength