Required Practical 2 (2 PARTS)

Question 1

Aim

Answer 1

Investigation of interference effects to include the Young’s slit
experiment and interference by a diffraction grating

Question 2

Double slit experiment, equipment:

Answer 2

○ Laser
○ Double slit
○ White screen
○ Metre ruler

Question 3

Double slit experiment, method:

Answer 3

Ensuring that the laboratory is
partially darkened, set up the apparatus as shown in the diagram. The single slit
might not be required if the laser beam is wide enough to illuminate both the slits of
the double slit.
○ Adjust the apparatus so that D is 0.500m, measured using the metre ruler.
○ Measure across a large number of fringes using the ruler and divide by the number
of fringe widths to find the fringe width w.
○ Increase D by 0.100m and repeat this, increasing it by 0.100m each time up to
1.500m.
○ Repeat the experiment twice more and find and record the mean w for each D.
○ If it is not quoted on the double slit, the slit separation must be measured using a
vernier calliper or a travelling microscope.

Question 4

Graphs and calculations

Answer 4