Anyone know how to solve the following problems? Thanks! 1.) An object is placed 12 cm to the left of a diverging lens of focal length -6cm. A converging lens of focal length 12 cm is placed a distance of d to the right of the diverging lens. Find the distance d that places the final image at infinity. 2.) Light of wavelength 460 nm falls on a diffraction grating with 5000 slits per cm. What is the required ditance from the slits to a screen if the spacing between the first and second dark fringes is to the 0.7m?