Practical 11 - Determination of wavelength using Young’s double slits

Question 1

What kind of graph do we plot for this practical?

Answer 1

Change in y against D

Question 2

What type of graph should we get after this practical?

Answer 2

Straight line

Question 3

What can we use the gradient of our change in y against D graph to determine?

Answer 3

The distance between the slits

Question 4

Draw the set-up of this practical

Answer 4

(See notes)

Question 5

What do we measure the fringe spacing using?

Answer 5

A ruler

Question 6

How do we measure the wavelength of the light from the laser?

Answer 6

We already know it - it says on the laser

Question 7

How do we measure the distance from the screen?

Answer 7

Vary it in equal intervals
Use a metre rule or digital calipers

Question 8

How can we determine the change in y if the fringes are particularly close together?

Answer 8

Using the separation of a number of fringes…
Determine by dividing the distance between the outermost fringes by the number of fringe gaps measured

Question 9

What’s actually makes observing the fringes more effectively and why?

Answer 9

Having slits closer together
Less uncertainty in measurements

Question 10

What are we work in out in this practical?

Answer 10

The distance between the 2 slits

Question 11

How can we calculate a, the distance between the slits?

Answer 11

a = wavelength/gradient

(As our graph is change in y against D - input this into the equation for Young’s experiment)