Section F: Optics

Question 1

what does inverse law mean

Answer 1

only the light hits surface direfctly

Question 2

what is cosine law

Answer 2

when illuminati surface is at an angle to the direction of light

Question 3

What is inverse law equation

Answer 3

E = I / d2

Question 4

Cosine law equation

Answer 4

E = I / D2 x cos (0)

Question 5

luminous flux

Answer 5

Rate of follow of light from the source, lumens

Question 6

Luminous Intensity

Answer 6

Intensity in a given direction

I - Candela

Question 7

Mean Spherical Intensity

Answer 7

The average value of luminous intensity all direction

Question 8

Illuminance

Answer 8

The luminous flux if a unit area of a surface in a given direction

Question 9

Photopic vision

Answer 9

Daylight vision
when the eye is light adapted
uses cone cells in central retina to give detailed, colour vision

Question 10

Scotopic Vision

Answer 10

Twilight vision
When the eye is dark adapted
Uses rod cells to give good low light perception

Question 11

Point source

Answer 11

infinity source of light

tiny dot that goes in every direction

Question 12

radian

Answer 12

angle subtended at the centre of a circle by an arc whose length is equal to the radius of the circle