Physics test 3

Question 1

What type of wave is a light wave?

Answer 1

Electromagnetic wave

Question 2

What are electromagnetic waves with frequencies that are a bit higher than visible light called?

Answer 2

ultraviolet (UV)

Question 3

Are electromagnetic waves longitudinal or transverse?

Answer 3

Transverse

Question 4

What are 2 things all electromagnetic waves have in common?

Answer 4

They are Transverse and travel at the same speed (3 x 10*8) in a vaccum.

Question 5

What are electromagnetic waves with frequencies that are a bit lower than visible light called?

Answer 5

Infrared (IR)

Question 6

Who was the first person to investigate infrared radiation?

Answer 6

British astronomer William Hesrschel

Question 7

During which years did he study Infrared radiation?

Answer 7

1738-1822

Question 8

How did he investigate infrared radiation?

Answer 8

he put a dark coloured filters on his telescope to help him observe the sun safely. He noticed that different coloured filters heated up his telescope to different extents and he wondered whether the different colours of light contained different ‘amounts of heat’

Question 9

What did he do to test this idea?

Answer 9

To test his idea he used a prism to split sunlight into a spectrum and the put a thermometer in each of the colours in turn. he also measured the temperature just beyond the red end of the spectrum ,where there was no visible light.

Question 10

Give me three examples of electromagnetic waves have higher frequencies than visible light.

Answer 10

Ultraviolet
X - rays
Gamma rays

Question 11

Give me three examples of electromagnetic waves have lower frequencies than visible light.

Answer 11

Infrared
Radio waves
Micro waves

Question 12

What are some uses of infrared radiation?

Answer 12

Infrared radiation can be used for short term communication such as communication between two computers in the same room or a tv to its remote. also the information sent along optical fibers is also sent using infrared radiation

Question 13

In simple terms how do thermal images work?

Answer 13

thermal images show the amount of infrared radiation given of by different objects

Question 14

What are some uses of Microwaves?

Answer 14

Micro waves are used for communications and satellite transmissions
including mobile phone signals

Question 15

How are radio waves produced?

Answer 15

radio waves are produced by oscillations in electrical circuits

Question 16

What are some uses of Radio waves?

Answer 16

Radio waves are used for transmitting radio broadcasts and TV programmes as well as other communications. Some radio communications are sent via satellite

Question 17

How are radio waves recieved?

Answer 17

A metal rod or wire can be used as an arial to receive radio waves

Question 18

What is refraction?

Answer 18

the bending of the pathway due to change in velocity

Question 19

How does ultraviolet disinfect water?

Answer 19

The energy transferred can kill microorganisms in the water

Question 20

Some materials absorb ultraviolet radiation and re-emit it as visible light. what is this called?

Answer 20

Fluorescence

Question 21

What are X-rays used for?

Answer 21

They can be used in medicine to make images of inside the body. They can also be for examining luggage for metal objects in airports

Question 22

What are Gamma rays used for?

Answer 22

They can be used to sterilize food and surgical instruments , they can also be used for detecting cancer

Question 22

How do you use Gamma rays detect cancer cells?

Answer 22

First we inject a chemical into the blood which collects inside cancer cells. This chemical emits gamma rays, then a scanner outside the body then locates the cancer by finding the source of the gamma rays

Question 23

How do microwaves heat up food?

Answer 23

microwaves can heat water and this specific microwave frequency is used in microwave ovens.

Question 24

Why could microwaves be dangerous to humans?

Answer 24

This heating could be dangerous to people because our bodies are mostly water so microwaves could heat up cells from the inside

Question 25

Why are high frequency waves more dangerous than low frequency waves?

Answer 25

they transfer more energy so they are potentially more dangerous.

Question 26

What are some risks of long exposure to x rays or gamma rays?

Answer 26

mutations may appear in DNA that can kill cells or cause cancer