HELPPP!! For the image of the overhead projector to be in focus, the distance from the projector lens to the image, di, the projector lenses focal length, f, and the distance from the transparency to the projector lens, do, must satisfy the thin lens equation 1/f=1/di+1/do. Which is the focal length of the projector lens if the transparency placed 4 inches from the projector lens is in focus on the screen, located 8 feet from the projectors lens ?
A. 0.375 in.
B. 6 in.
C. 0.167 in.
D. 3.84 in.

Question

HELPPP!! For the image of the overhead projector to be in focus, the distance from the projector lens to the image, di, the projector lenses focal length, f, and the distance from the transparency to the projector lens, do, must satisfy the thin lens equation 1/f=1/di+1/do. Which is the focal length of the projector lens if the transparency placed 4 inches from the projector lens is in focus on the screen, located 8 feet from the projectors lens ? 
A. 0.375 in. 
B. 6 in. 
C. 0.167 in. 
D. 3.84 in.

yournightmare · Answer

i believe it is b.

yournightmare · Answer

I might be wrong. Try www.mathway.com