Investigation of interference effects to include the Young's slit experiment and interference by a diffraction grating Flashcards
1
Q
why is a laser used
A
monochromatic
coherent
2
Q
What is D adjusted to ?
A
- D adjusted between the grating and the screen until a number of orders can be seen
- sufficiently far apart for their seperation to be measured witha milimetre scale
3
Q
taking measurement
A
- not done directly
- centre of maxima marked on a piece of paper secured to the front of the screen
- then processed after the laser has been switched off
4
Q
What are the precautions when using a laser
A
- never look directly into beams or allow anyone else to
- never point the beam at anyone
- avoid reflection of the beam
- always keep your back to the laser when it is on
- always switch of when not in use
5
Q
why are measurements made as large as possible
A
minimise experimental uncertainty
6
Q
when not using a laser why is light passed through a laser first
A
coherent
