Required Practical 2 Flashcards
What does required practical 2 investigate?
Its an investigation of the interference effects by Young’s slit and diffraction by a diffraction grating.
Describe the method for a double slit diffraction
1, Set up the equipment, with a laser (one with a beam that is broad enough to illuminate across both slits) a double slit with a separation s (can be measured with a vernier calliper) and a screen which is D distance away.
2, Darken the room
3, Adjust the laser so the light coming from it is evely spread over the two slits.
3, Visible fringes will to shown on the screen.
4, Count across a number of fringes and divided by the number of gaps between them, 10 fringes you would divide by 9. This will give you w.
5, Change the distance of D and measure the fringe width each time.
6, Draw a graph of w on the x axis against D on the y axis. The graph should be a straight line through the origin.
7, The gradient is lander/slit separation
Describe the method for the diffraction grating
1, Set up with the laser, then the diffraction grating with a screen a distance D apart.
2, Shine the laser through the grating and the orders will be visible on the screen.
3, The angles of the order can be obtained by working out the distance between the orders and the distance to the screen and using trig you can work out the angle.
