PLEASE HELP!! I ONLY HAVE A LIMITED AMOUNT OF TIME!!!

A photographer is designing a camera lens that works to reduce the reflection of red visible light. He is working to avoid reflecting light that has a wavelength of 720 nm in air. What should be the width of the coating on the camera lens?

180 nm
360 nm
1400 nm
2900 nm

Question

PLEASE HELP!! I ONLY HAVE A LIMITED AMOUNT OF TIME!!!

A photographer is designing a camera lens that works to reduce the reflection of red visible light. He is working to avoid reflecting light that has a wavelength of 720 nm in air. What should be the width of the coating on the camera lens?

180 nm
360 nm
1400 nm
2900 nm

anonymous · Answer

just a moment im figuring it out.

anonymous · Answer

how much time do you have?

anonymous · Answer

i think its the third

anonymous · Answer

less than 10 minutes now @grabill

anonymous · Answer

im pretty sure its the third.

anonymous · Answer

Think about the typical wavelengths of red light. For the coating to be effective, its thickness must be such that indident and reflected light is a half wavelength out of phase. Hope this helps.