Unit 3

Question 1

Define Waves

Answer 1

vibrations, which carry or move energy and information without transferring matter.

Question 2

Define transverse waves
Provide examples

Answer 2

a wave that vibrates or oscillates at right angles to the direction in which the energy or wave is moving. I.e. EM spectrum waves and water surface

Question 2

Define Wavefronts

Answer 2

a line where all the vibrations are in phrase and the same direction from the source.

Question 2

Define Longitudinal wave,
Provide examples

Answer 2

a wave that vibrates or oscillates along the direction in which the energy or wave is moving. I.e. sound waves

Question 3

Define Amplitude

Answer 3

the maximum movement of particles from their resting or equilibrium position; ( Always a positive number).

Question 4

Define frequency and how it is measured.

Answer 4

The number of waves or vibrations made each second. Measured in Hertz (Hz)

Question 5

Define Wavelength

Answer 5

the distances between a particular point on a wave and the same point on the next wave, e.g., from crest to crest or from tough to tough.

Question 6

Define Time period

Answer 6

time needed to make one complete wave or vibration. Measured in second(s).

Question 7

Define the Law of reflection

Answer 7

The angle of incidence (Î) is equal to the angel of reflection (^r)

Question 8

Normal

Answer 8

imaginary line at right angles to a surface.

Question 9

Angle of incidence

Answer 9

angle between the direction of the incident wavefronts and the normal.

Question 10

Angle of reflection

Answer 10

Angle between the direction of the reflected wavefronts and the normal.

Question 11

Refraction

Answer 11

Change in direction of a wave due to the changes in its speed when entering a different medium. E.g., travelling from air to water ( slower wave) or from glass to water (faster wave).

Question 12

Doppler effect

Answer 12

the change in frequency and wavelength caused by the relative movement of the source of waves or the observer.

Question 13

Electromagnetic Spectrum

Answer 13

A continuous spectrum of waves that includes radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma-ray radiations.
( In this order waves start with a very long wavelength and love frequency and they finish with a very short wavelength and high frequency.

Question 14

What properties does the EM Spectrum have in common?

Answer 14

1. They transfer energy ( information)
2. They are transverse waves
3. They travel at 300000000 m/s (the speed of light in a vacuum, (= free space)).
4. They can be reflected and refracted.