If you take a picture of your friend, who is standing 3.90 m from the lens, using a camera with a lens with an 85 mm focal length, how far from the sensor is the lens

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

A1.5m wire carries a 2 a current when a potential difference of 52 v is applied. what is the resistance of the wire?

What describes the formation of horizon b? a. forms at the surface b. features parent material c. undergoes the most change d. forms due to decomposed material i think the answer is c. undergoes the most change