P13 (Electromagnetic Waves)

Question 1

Electromagnetic Waves

Answer 1

• transverse waves transfers energy from a source go the absorber
• same speed through air and vacuum

Question 2

Order if Em spectrum

Answer 2

• Radio waves
• microwaves
• infrared
• visible light
• Ultra Violet
• X rays
• gamma rays

Question 3

As waves go from radio to gamma…

Answer 3

• increases frequency

- decreases wavelength

Question 4

Altering current to produce radio waves

Answer 4

• in transmitter the electrons oscillates and produces Em waves
• emits radio waves and transmits energy
• receiver absorbs and causes electrons to oscillate

Question 5

Use of Radio Waves

Answer 5

• communication (radio and tv)

- waves diffract around the curved surface for signal to reach different places in the world

Question 6

2 Uses of microwaves

Answer 6

• microwaves sent to signal and transferred back to earth
• can travel through watery atmosphere for Tv and phones
• in microwaves to heat food as it penetrates the food to heat up the water molecule

Question 7

3 uses of Infrared Radiation

Answer 7

• infrared cameras detect temperature so brighter light on screens= higher temperatures
• heat up food when absorbed
• electrical heaters and objects absorb it to heat room

Question 8

Fibre Optics

Answer 8

• thin glass or plastic fibres carry data

- reflection of visible light along the glass bouncing

Question 9

2 Uses of Ultraviolet Radiation

Answer 9

• from the sun and tanning salons for a tan

- used for lights which are energy efficient and last long

Question 10

How X-rays and Gamma rays are used in medicine

Answer 10

• pass through body but can’t penetrate bone so it produces images of the bones
• gamma rays kill cancer cells, as they’re focused on the specific area
• used for medical tracers to detect problems as they can see through body

Question 11

3 ways Em waves harm people

Answer 11

• UV can cause sunburn and skin cancer
• UV causes blindness
• X Rays and Gamma rays produce ionising radiation that knock off the electrons causing mutation in cells (in genes)

Question 12

Radiation dose

Answer 12

• risk of harm to he body when being exposed to radiation

- depends on how much and what radiation

Question 13

Visible Light

Answer 13

• ROYGBIV
• primary colours and red, green and blue and you can’t mix
• mix all creates white light

Question 14

Absorbing in white and black objects

Answer 14

• white light reflects all equally

- black light absorbs all light

Question 15

Colour filters

Answer 15

Filter out different wavelengths of light so that only certain colours are absorbed

Question 16

Black Bodies

Answer 16

• perfect black body is an object that absorbs all radiation (none reflected or transmitted)

Question 17

Effect of shorter wavelength on intensity

Answer 17

shorter wavelengths increase intensity more rapidly than longer
wave lengths as it increases temp, causing the peak wavelength to decrease

Question 18

How radiation effects temperature

Answer 18

• in day earth absorbs it during the day to increase local temps
• at night less absorption that being emitted so decrease temp
• earth keeps at constant temp apart from global warming