chapter 4: Electromagnetic Radiation

Question 1

the speed of electromagnetic waves travelling in a vacuum is equal to

Answer 1

300,000 km/second

Question 2

two types of ways maybe generated by using a slinky. The particles in the slinky move in the same direction as the wave in the following type (or types) of waves

Answer 2

longitudinal

Question 3

all electromagnetic waves have the same … in a vacuum

Answer 3

speed

Question 4

which of the following ways has the lowest frequency?

Answer 4

Radio waves
AM - slowest
FM

Question 5

which of the following waves have the longest wavelength?

Answer 5

gamma rays

Question 6

Wireless Internet is a method of transmitting an Internet connection using radio waves. Which of the following devices also uses radio waves for communication?

Answer 6

tVs, Wi-Fi, radios

Question 7

which colours are absorbed by a red filter?

Answer 7

everything but red

Question 8

What colour will a ? object placed in a green light appear to be?

Answer 8

Black

Question 9

optical fibre is widely used to transmit digital signals for communications. Optical fibre:

Answer 9

optical fibre is better than copper:
greater bandwidth
faster
less interference

Question 10

according to the wave equation , if the speed of a wave stays the same but its wavelength decreases, then the frequency of the wave will

Answer 10

increase

Question 11

televisions use which of the following types of radio waves to carry information for the video and audio signals

Answer 11

FM

Question 12

this diagram shows the use of electromagnetic radiation in communications. some microwaves are used to reflect from communications satellites.

deduce which statement below is correct

Answer 12

shorter wavelengths can penetrate the atmosphere longer wavelengths can not however they can travel further

Question 13

one use of infrared cameras is to locate people lost at sea or in remote areas.

deduce why these cameras can be used at night

Answer 13

don’t need normal visible light to see people. we pick the infrared emitted from their warm bodies

Question 14

which of the following types of electromagnetic radiation poses the poses the most threat to humans?

Answer 14

UV. X-rays. Gamma

Question 15

when light has been polarised it has

Answer 15

polarisation makes EM light one-dimensional —> less damage to eyes

Question 16

Isaac Newton discovered when white light is passed through a prism, it shows the colours of the rainbow when it exits The prism! Which of the following list guess all the colours in order starting from red

Answer 16

R ed
O range
Y ellow 
G reen 
B lue
I 
U

Question 17

What devices used to receive radio waves?

Answer 17

Antenna

Question 18

When radio waves are received, they are first converted into

Answer 18

Sound waves

Question 19

A wave at the beach has a frequency of 0.2 Hz. If it’s wavelength is 15m, calculate its speed using the formula V = F {

Answer 19

0.2 x 15

Question 20

The electromagnetic spectrum can be best described as

Answer 20

electromagnetic radiation

Question 21

Polarisation of light involves

Answer 21

ways of light. In different orientation being absorbed by a filter

Question 22

Optical fivers container beam of light inside and even when they are bent to turn around corners because of which of the following principles

Answer 22

What allows optical fivers to be bent around Kaunas is total internal reflection

Question 23

Which of the following objects which allowed the most x-rays to pass through it

Answer 23

X-rays cannot passthrough lead

Question 24

What can be said about the speed of light in a glass prism

Answer 24

Light slows down in a glass prism

Question 25

primary colours

Answer 25

Red, green, blue

Question 26

secondary colours

Answer 26

Cyan, yellow, magenta

Question 27

Explain why they are called primary colours

Answer 27

We can combine them to make all the colours of light

Question 28

Explain why they are called secondary colours

Answer 28

They are produced when two primary colours overlap