Light Physics gcse

Question 1

what is the law of reflection

Answer 1

Its when a ray of light reflected from a plane surface, The angle of reflection is equal to the angle of incidence

Question 2

What are the properties of an image in a plane mirror

Answer 2

• Laterally inverted
• Same size
• Same distance
• Virtual image

Question 3

What is the definition of Virtual image

Answer 3

It is an image that cant be focused onto a screen

Question 4

What happens to light traveling into a glass block

Answer 4

The light bends towards the normal (slows down)

Question 5

What is the definition of Refracted

Answer 5

when something Changes directions

Question 6

What is dispersion

Answer 6

When white light is separated into 7 colours using glass prism

Question 7

what are the 7 colours of the visible spectrum in order

Answer 7

Red
Orange
Yellow 
Green 
Blue 
Indigo 
Violet

Question 8

Why does dispersion happen

Answer 8

As all colours of the visible spectrum travel at the same speed in a vacuum (or air) But colours have different frequencies therefore different wavelength meaning they slow down by different amounts when entering glass so they refract at different amounts

Question 9

What colour has the biggest wavelength

Answer 9

Red

Question 10

What colour bends the most through prism

Answer 10

Violet

Question 11

What colour slows down the least when passing through a prism

Answer 11

Red

Question 12

What colour slows down the most when passing through a prism

Answer 12

Violet

Question 13

Define the critical angle

Answer 13

When the angle of incidence is in an material (air, glass), the angle of refraction in air is 90 degrees

Question 14

What is in the critical angle for glass

Answer 14

42 degrees

Question 15

What are the uses for total internal reflection

Answer 15

Periscopes

Reflectors

Question 16

What is total internal reflection

Answer 16

When the ciritical angle is over 42 and there is no refraction.

Question 17

What are fibre-optic used for

Answer 17

Used in communication for carrying signals.

An endoscope.

Question 18

Advantages and disadvantages of communications (fibre optic)

Answer 18

Advantages- Carry more information than copper at the same diameter.
Disadvantages- Signal needs to be boosted every few km

Question 19

Advantages and Disadvantages of endoscopy (Fibre optic)

Answer 19

Advantages- See inside patients body without needing large hole.
Disadvantages- May be uncomfortable, cause sore throat

Question 20

what happens when the angle of incidence is above 42 degree

Answer 20

Total internal reflection