chapt 5 : ray model of light

Question 1

how does light travels

Answer 1

in a striaght line

Question 2

what are luminous objects

Answer 2

objects that emit light on their own

Question 3

what are non-luminous objects

Answer 3

objects that do not emit light on their own

Question 4

how do we see non-luminous objects

Answer 4

when they are near a light source, they will reflect the light from the object and enters our eyes

Question 5

how do we see luminous objects

Answer 5

light emitted by them enters our eyes

Question 6

definition of reflection

Answer 6

when light is being bounced off a surface

Question 7

what is a plane mirror

Answer 7

a mirror that has a flat and smooth surface

Question 8

what are 3 characteristics of the plane mirror

Answer 8

the image is upright,
it is laterally inverted
and the image shown is the same size as the object.

Question 9

what are 3 uses of plane mirror

Answer 9

check appearance
used in interior design to make the house look bigger
to reflect eye chart so that it appears further

Question 10

types of curve mirror

Answer 10

convex and concave

Question 11

what are 3 uses of convex mirror

Answer 11

blind spot mirror at the road junction
security mirrors
side or rear view mirror in the car

Question 12

what is a convex mirror

Answer 12

a mirror that has a diminished image and provides a wider field of vision

Question 13

what is the characteristic of the convex mirror

Answer 13

it buldges out

Question 14

what are 5 uses of concave mirror

Answer 14

make-up mirror
dental mirror
torch light
headlight of car
microscope mirror

Question 15

what is a concave mirror

Answer 15

a mirror that provides a bigger field of vision and a larger image

Question 16

what is the characteristic of concave mirror

Answer 16

it buldges inwards

Question 17

what happens when the reflecting surface is rough

Answer 17

most of the light is absorbed and most of the light will be reflected in a scattered manner. this is called diffuse reflection

Question 18

what happens when the reflecting surface is smooth and flat

Answer 18

light will be reflected in one direction and this is called regular reflection.

Question 19

what happens when light passes through different mediums

Answer 19

it will bend at the boundary due to the change in speed of light in the medium, this bending of light is known as refraction

Question 20

what happens to the bending and the speed of light when it enters a denser medium

Answer 20

the light will bend towards the normal and the speed slows down.

Question 21

what happens to the bending and the speed of light when it enters a less dense medium

Answer 21

the light will bend away from the normal and the speed increases.

Question 22

what happens to the light when it enters a perpendicular medium

Answer 22

it will not bend

Question 23

will the object in a dense medium appear to be closer or further

Answer 23

closer

Question 24

what are the colours in the spectrum

Answer 24

red
orange
yellow
green
blue
indigo
violet

Question 25

what are the uses of infrared radiation

Answer 25

tv remote control
cooking
motion detector
burglar alarm
thermal imaging cameras

Question 26

what are the harmful effects of IR

Answer 26

temperature increase
damage to eye

Question 27

what are the uses of UV

Answer 27

to sterilise medical equipments
disinfect drinking water
helps produce vitamin
sunbed for tanning

Question 28

what are the harmful effects of UV

Answer 28

harms eye
causes skin cancer

Question 29

uses of visible light

Answer 29

photosynthesis
enable us to see

Question 30

harmful effects of visible light

Answer 30

causes chemical change in some materials
light pollution
blue light from electronic devices affects our sleep
affects an animal’s ability for carry out daily activities