If you have a printer, print out this page to keep a record of your measurements and calculations. If you do not have a printer, you could copy this sheet by hand.
| w = | vernier reading 2 - reading 1 | = | - | = mm |
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| number of fringes | ||||
| = m | ||||
| s = | mm = m | |||
| D = | m | |||
Substitute values in metres into equation to calculate l.
| l = | ws | = | × | = m |
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| D |
