A double-slit experiment is performed with light of wavelength 650 . The bright interference fringes are spaced 1.3 apart on the viewing screen. What is the distance, d, between slits.

So far, I know that the appropriate equation to use is "delta y = (lambda L)/d". I also know that y is given (1300 micrometers) and lambda is given (0.650 micrometers).

The problem I'm having is that I have two unknowns, and there is no further information. I would use trigonometry to find the angle measure in radians, but I don't have a L between the slits and the screen.

Question

A double-slit experiment is performed with light of wavelength 650 . The bright interference fringes are spaced 1.3 apart on the viewing screen. What is the distance, d, between slits.

So far, I know that the appropriate equation to use is "delta y = (lambda L)/d". I also know that y is given (1300 micrometers) and lambda is given (0.650 micrometers). 

The problem I'm having is that I have two unknowns, and there is no further information. I would use trigonometry to find the angle measure in radians, but I don't have a L between the slits and the screen.

vincent-lyon.fr · Answer

True! Distance from slits to screen is missing.

anonymous · Answer

1.3 / L is equal to lamda / y
Isn't y the distance between the slits? 1300 micrometers?
what are the units of the number 1.3?