Posted by Jon on .
1)An object of height 4 cm is placed at a distance of 20 cm from a convex lens of focal length 10 cm. Find the nature of the image.
1/f=1/d1+1/do
d1=fdo/dof
(10)(20)/2010
d1=20
m=(20)(4)/20
4 or 4 away
answer: real, inverted
2)Light passes from air into water at 45.0 d/C to the normal. If the index of refraction of water is 1.33, find the angle of refraction.
sin1((1.00/1.33)sin45.0
32.1 d/C

Physics 
drwls,
The numbers are correct, but I am not familiar with your "d/C" notation. I hope it has nothing to do with degrees C, which is a unit of temperature, not angle. Anglemeasuring units are just called "degrees".