A convex lens of focal length 10 cm forms image of object placed 30 cm in front of the lens. Find the magnification?
To find the magnification of an image formed by a convex lens, you can use the lens formula:
1/f = 1/v - 1/u
Where:
f is the focal length of the lens
v is the image distance from the lens
u is the object distance from the lens
Given:
focal length (f) = 10 cm
object distance (u) = 30 cm
We can rearrange the lens formula to solve for image distance (v):
1/v = 1/f - 1/u
Substituting the given values:
1/v = 1/10 - 1/30
Now, let's calculate the value of 1/v:
1/v = (3 - 1) / 30
= 2/30
= 1/15
Taking the reciprocal on both sides:
v = 15 cm
Now, we can find the magnification (M) using the formula:
M = -v/u
Substituting the values:
M = -15/30
= -1/2
Therefore, the magnification of the image formed by the convex lens is -1/2. The negative sign indicates that the image is inverted compared to the object.