A low-pressure sodium vapor lamp whose wavelength is 5.89 x 10−7 m passes through double-slits that are 6.7 x 10−4 m apart and produces an interference pattern whose fringes are 3.2 x 10−3 m apart on the screen. What is the distance to the screen?

2.7 meters
3.0 meters
3.6 meters
4.2 meters

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.