waves and Electro magnetism

Question 1

what is the order of the electro magentic spec and what can each waves be used for ?

Answer 1

Radio - communication
Micro - cooking
Infra Red - Broadband
Visible - normal
UV - security/ detecting bank notes
X rays - medical
Gamma - sterilisation

Question 2

what does a black body do?

Answer 2

absorbs all radiation

Question 3

how to measure speed of sound practical ?

Answer 3

• stand anywhere from 100m to 300m away (so you can still see the signal)
• get a person to wave a flag as the fire a starting gun

start the stop watch when they lower their hand

stop the stop watch when the sound reaches you

Question 4

what are transverse waves ?

Answer 4

• oscillations are perpendicular to the direction of travel
• water, electromagnetic, light

Question 5

what are longitudinal waves ?

Answer 5

waves that oscillate parallel to the direction of energy transfer

sound and shock waves

Question 6

what happens when a wave is absorbed?

Answer 6

the energy from the wave is stored in the energy stores of the object

Question 7

does a wave travel at higher or lower speeds through a dense object ?

Answer 7

slower speeds

when the object is more dense it bends towards the normal

Question 8

refraction of waves equation ?

Answer 8

V = F x Lambdar

Question 9

why do diffrent colours of light refract at diffrent angles ?

Answer 9

because each colour of light travels at diffrent speeds through glass because each colour has a slightly diffrent wavelength and frequency

Question 10

which colours are slowed down the most and least by glass.

Answer 10

Red - slowed down the least and reflects the least

Violet - slowed down the most and reflects the most

Question 11

why do all electromagnetic waves oscillate up and down ?

Answer 11

because all electromagnetic waves are transverse waves

Question 12

why are waves inversely proportional ?

Answer 12

because when wavelength increases, frequency decreases and vice versa

Question 13

where do Gamma rays come from ?

Answer 13

radioactive decay

Question 14

where do X - rays , visible and UV rays come from ?

Answer 14

when electrons drop down shells

Question 15

where do infra red molecules come from ?

Answer 15

when the bonds that hold molecules together vibrate

Question 16

how do Radio waves transmit communication ?

Answer 16

• Radio waves have the smallest frequency and biggest wavelength
• because radio waves are in the electromagnetic spec it means we can generate an mag field around them and generate them into electricity.
• we can detect radio waves on something called a Oscilloscope
• this lets us see the frequency and wavelength of transmitted waves.

if we wanted to communicate the number 800 we would just use a 800 hz frequency