Waves for communications and the universe

Question 1

Waves transfer what?

Answer 1

Energy.

Question 2

Waves can either be what type?

Answer 2

Transverse or longitudinal.

Question 3

EM waves are what type of waves?

Answer 3

Transverse.

Question 4

Sound waves are an example of what type of waves?

Answer 4

Longitudinal.

Question 5

EM stands for…

Answer 5

…the electromagnetic spectrum.

Question 6

Longitudinal waves show areas of what and what?

Answer 6

Compression and rarefaction.

Question 7

Waves can be reflected,…

Answer 7

…refracted and diffracted.

Question 8

Waves under go what when they are refracted at an interface?

Answer 8

A change in direction.

Question 9

All waves obey the wave equation with the formula:

Answer 9

v = f x lambda

v = velocity in m/s
f = frequency in Hz
lambda = wavelength in m

Question 10

What waves of the EM spectrum can be used for communications?

Answer 10

Radio waves (TV and radio), microwaves (phone signal), infrared (remote controls) and visible light (photography).

Question 11

What is the normal?

Answer 11

A construction line perpendicular to the reflecting surface at the point of incidence.

Question 12

The angle of incidence is equal to…

Answer 12

…the angle of reflection.

Question 13

The image produced by a plain mirror is a…

Answer 13

…virtual image.

Question 14

Sound waves are longitudinal and cause…

Answer 14

…vibrations within a medium.

Question 15

Pitch of sound is determined by what?

Answer 15

Its frequency.

Question 16

Loudness of sound is determined by what?

Answer 16

Its amplitude.

Question 17

An echo is a what of sound?

Answer 17

Reflection.

Question 18

If a wave source is moving relative to the observer what happens?

Answer 18

There is a change in the observed wavelength. This is known as the Doppler Effect.

Question 19

There is an increase in wavelengths of light from the most distant galaxies. Why is this?

Answer 19

The further away a galaxy is the faster that it is moving away and the bigger the observed increase in wavelength. This is known as red-shift as the wavelength is increasing towards the red end of the spectrum.

Question 20

The observed red-shift provides evidence for what theory of the beginning of the universe?

Answer 20

Evidence for the Big Bang. This is because if we reverse the effect of red-shift with time the universe contracts to form an infinitely small, infinitely dense singularity from which everything must have occurred.

Question 21

What is CMBR and what does it stand for?

Answer 21

Cosmic Microwave Background Radiation. It is radiation that fills the universe and was present shortly after the beginning of the universe.

Question 22

What theory of the beginning of the universe is the only theory that can explain CMBR?

Answer 22

The Big Bang.