Ido not know why but the answer is 684 let me know why.  a light with a second-order dark band forms a diffraction angle of 20.0°. the diffraction grating has 200.0 lines per mm.the wavelength of the light, to the nearest whole number, is    nm.

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

Two balls, each with a mass of 0.5 kg, collide on a pool table. is the law of conservation of momentum satisfied in the collision? explain why or why not

Arope has one end tied to a vertical support. you hold the other end so that the rope is horizontal. if you move the end of the rope back and forth with a frequency of 4 hz, the transverse wave you produce has a wavelength of 0.5 m. what is the speed of the wave in the rope?