P3.2-Light

Question 1

What is parallel beam of light?

Answer 1

all the beams are travelling straight

Question 2

What is a beam?

Answer 2

Streams of lights shown by several rays

Question 3

What is divergent beam of light?

Answer 3

all the beams are dispersing into different directions

Question 4

What is convergent beams of light?

Answer 4

All the beams are combining at one point

Question 5

What is the Normal?

Answer 5

A line perpendicular to the mirror at the point where incident ray strikes (90°)

Question 6

What is the speed of light?

Answer 6

3x10⁸ m/s

Question 7

What is a real image

Answer 7

an image that can be produced on a screen and is formed by rays that pass through the screen

Question 8

What is a virtual image

Answer 8

a virtual image is produced by rays that seem to come from the object but do not pass through it.

Question 9

Is the image on a mirror real or virtual?

Answer 9

Virtual (rays are reflected)

Question 10

What is the refractive index (n)?

Answer 10

the ratio of light speed in air to light speed in the medium

Question 11

Refractive index of glass

Answer 11

1.5

Question 12

Refractive index of water

Question 13

What is the formula for refractive index involving speed of light?

Answer 13

n= speed of light in air/ speed of light in medium

Question 14

What is the formula for refractive index involving sin?

Answer 14

n = sin(i)/ sin(r)
i= angle of incidence
r= angle of refraction

Question 15

What is the Critical angle?

Answer 15

when the refracted angle is 90°

Question 16

What happens when angle of Incidence goes greater than critical angle?

Answer 16

total internal reflection- light reflects inwards towards the medium

Question 17

Equation for Critical angle

Answer 17

Sin(c)= 1/n

Question 18

What type of rays are coming from an object at distance?

Answer 18

Parallel rays

Question 19

What does a thin converging lens do to a parallel beam of light?

Answer 19

it narrows them at the focal point

Question 20

Define principal axis [2]

Answer 20

The line through the optical center of a lens. Right angle to the lens.

Question 21

Define Principal focus [2]

Answer 21

1. same as focal point
2. point on the axis where either parallel light rays converge, or diverge from

Question 22

Define focal length

Answer 22

Distance between the center of the lens, to the focal point

Question 23

In what order is the focal point named?

Answer 23

2F1, F1, F2, 2F2

Question 24

at infinity- position, image size and nature [3]

Answer 24

1. At f2
2. Highly diminished
3. Real and inverted

Question 25

beyond 2F1- position, image size, and nature [3]

Answer 25

1. between f2 and 2f2 2. diminished 3. Real and inverted

Question 26

At 2F1- position, image size, and nature [3]

Answer 26

1. At 2F2 2. Same size 3. Real and Inverted

Question 27

between F1 and 2F1- position, image size, and nature [3]

Answer 27

1. Beyond 2F2 2. Magnified 3. Real and inverted

Question 28

At F1- position, image size, and nature [3]

Answer 28

1. At infinity 2. Infinitely large 3. Real and inverted

Question 29

Define monochromatic

Answer 29

Light of one colour- one frequency- is called monochromatic

Question 30

Define Spectrum

Answer 30

the band of colours

Question 31

What are the 7 spectrum colors in order- decreasing wavelength. [7]

Answer 31

Red, Orange, Yellow, Green, Blue, Indigo, Violet

Question 32

Which color has the highest frequency, shortest wavelength

Answer 32

Violet

Question 33

Which color has the lowest frequency, longest wavelength

Answer 33

Red

Question 34

application of convex lenses [2]

Answer 34

1. long sightedness 2. convex lenses used to focuz light rays closer before they enter eye