WAVES

Question 0

Vibrations travel via a medium.

Answer 0

Most waves are mechanical: they require a physical medium. Electromagnet waves transfer via changes in magnetic and electric fields.

Question 1

All waves transfer energy from one place to another.

Answer 1

Waves are usually set up by oscillations in a material. An oscillation is a vibration, a repeating back and forth motion.

Question 2

What are the two types of waves?

Answer 2

Longitudinal and transverse.

Question 3

What is the difference between a transverse and longitudinal wave?

Answer 3

Transverse waves is where the particles move at right angles to the direction of a wave. A longitudinal wave transfers energy parallel to the medium, in the direction of a wave.

Question 4

What is the equation for wave speed?

Answer 4

Wave speed=frequency(Hz) X wave length(m)

Question 5

When waves hit a surface, what are the three things that can happen to them?

Answer 5

Reflected, transmitted, or absorbed!

Question 6

When objects have a rough uneven surface, what happens to the light being reflected?

Answer 6

Light will reflect in all directions.

Question 7

Smooth surfaces reflect evenly.

Answer 7

All incident rays reflect off at the same angle in smooth surfaces.

Question 8

Images in a plane mirror are:

Answer 8

Upright but back to front, the image is as far behind the mirror as the object is in front, and are virtual images.

Question 9

A real image is where real light meets. The rays pass through the image and the image can be touched, like an image projected into a surface.

Question 10

Refraction happens when?

Answer 10

A wave changes speed at a boundary between one medium and another.

Question 11

If the wave meets the boundary at an angle to the normal the ray is bent.

Answer 11

Angle of refraction is smaller than the angle of incidence.

Question 12

If the wave speeds up as it enters a medium, it bends away from the normal.

Answer 12

If the wave slows down on entry to a medium it bends towards the medium.

Question 13

Refraction (light) only changes direction due to a change of speed, and has to be at an angle to the transparent medium.

Question 14

TAGAGA stands for what?

Answer 14

Towards
Air
Glass

Away
Glass
Air

Question 15

The refraction index of a material is the ratio of the speed of light in the material.

Question 16

Two ways of working out the refractive index are?

Answer 16

Refraction index(n)=sin i%sin r

I=angle of incidence
R=angle of refraction

Question 17

Glass and water are denser than air.

Answer 17

Refraction makes water appear shallower than it is

Question 18

TIR (Total internal reflection)

Answer 18

Only occurs when light ray goes from a dense medium to a less dense medium.
Beyond a certain angle to the normal, all light is reflected from the boundary, back into the denser material.
This is called the criticle angle.