Practical 10 - Measurement of the intensity variations for polarisaton

Question 1

Describe the light waves in a ray of light from a lamp

Answer 1

Vibrations in all planes and directions
Unpolarised

Question 2

Describe the light through a Polaroid filter

Answer 2

Vibrations in one plane/direction only
Polarised

Question 3

What does the 1st Polaroid filter always do?

Answer 3

Polarise the light

Question 4

In which case will light NOT pass through the second polarising filter?

Answer 4

If the direction in which the second filter polarises light is at right angles to the polarising direction of the 1st Polaroid

Question 5

What’s the method for this practical?

Answer 5

Investigate variation in intensity of light by looking through the lamp through both Polaroids and rotating one of the Polaroids through 360 degrees
Note the change in intensity occurring

Question 6

What’s intensity of light measured in?

Answer 6

Lux

Question 7

What’s lux the unit of?

Answer 7

Intensity (of light)

Question 8

What are we investigating in this practical?

Answer 8

Variation in intensity of light

Question 9

What do we rotate the Polaroid through?

Answer 9

360 degrees

Question 10

What’s the result of this practical?

Answer 10

Brightness goes from maximum to minimum every 90 degrees

Question 11

What do we use to measure the intensity of light?

Answer 11

A lux metre

Question 12

What’s the angle between the two maximum intensities of light?

Answer 12

180 degrees

Question 13

How does the reading vary between a maximum and minimum value?

Answer 13

Sinusoidally