Topic 4, Waves

Question 1

Define simple harmonic motion (SHM).

Answer 1

Motion in which: The acceleration is proportional to, and in the opposite direction of, the displacement from the equilibrium position.

TWO KEY THINGS: PROPORTIONAL AND OPPOSITE DIRECTION!! (a prop -(constant)x or F prop -(constant)x)

Question 2

What does the graph for SHM look like? (a-x graph). VERY IMPORTANT, many Qs on this and definition SHM

Answer 2

Straight line through the origin (since a=-constantx so linear and no y-intercept) going from “left/2nd quadrant” pos a to origin to “4th quadrant” x

Question 3

What is x in SHM?

Answer 3

DISPLACEMENT FROM THE EQUILIBRIUM

Question 4

What are the “conditions” for total internal reflection? Define critical angle

Answer 4

The critical angle is the angle of incidence where the angle of refraction is 90deg. The light must travel from an optically more dense to a less dense medium.
Critical angle = sin^-1 (nr/ni)

Total internal reflection is when angle>critical angle

Question 5

Difference standing waves and Normal

Answer 5

The wave doesn’t move; oscillates in one place (points only move up and down, wave doesn’t move horizontally)
No other waves in between frequencies

Question 6

Antinode vs Node

Answer 6

Antibode = point where stationary wave OSCILLATES THE MOST

Node = STATIONARY POINT

Question 7

What is meant by polarized light?

Answer 7

Light in which the electric field oscillates in a single plane.

Question 8

Unpolarized light

Answer 8

The electric fields oscillate in all planes that lie along the direction of propagation