find the focal length of lens of power -2D .what type of length is this plzz fast
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Answered by
174
The power of the lens given is -2D.
It has negative sign, which means that it is a concave lens.
Now, the formula for the power is P = 1/f.
Let’s put the given value. -2 = 1/f
On simplifying we get, f = -1/2 m
By converting the result into centimetres, we get, f = -1/2 X 100
Therefore, focal length =-50cm.
It has negative sign, which means that it is a concave lens.
Now, the formula for the power is P = 1/f.
Let’s put the given value. -2 = 1/f
On simplifying we get, f = -1/2 m
By converting the result into centimetres, we get, f = -1/2 X 100
Therefore, focal length =-50cm.
Answered by
14
Answer:
The formula is
P(diopter) = \frac{1}{f (metres)}
f=\frac{1}{-2}
= -0.5m
when focal length is negative then it is concave lens.
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