Worksheet B2
Thickness of a hair
The human hair is very thin and you cannot measure it by the mean of ordinary meters, such as a ruler. Even if we measured it by the mean of more expensive meters, the precision would be very small. The only method we can use is the method of difraction of a coherent monochromatic radiation beam (laser).
Task: Measure the radiant of your hair
Tools: laser pointer, a meter, a hair, a shade made of a sheet of graph paper, calculator, sellotape
Procedure:
Measure the needed parametres and calculate the radius of the hair by the means of the aforementioned property
where s is the distance of the two minima of the same order (the middle of the two first dark points on the shade) in millimetres, d is the distance of the fibre from the shade in millimetres and λ wavethlenght of the used lifgt is λ = 532 nm.
Erasmus+ 74