In an experiment a convex lens of focal length 15 cm is placed coaxially
Answers
Answer:
Explanation:
As we learnt in
Mirror Formula -
\frac{1}{v}+\frac{1}{u}=\frac{1}{f}
- wherein
u= Object distance from pole of mirror.
v= Image distance from pole of mirror.
f= focal length of the mirror.
Given focal length of lents (f) = 1.5 cm
Object distance u = - 20 cm , f = 15 cm
We know that \frac{1}{f}=\frac{1}{v}-\frac{1}{u}=\frac{1}{v}=\frac{1}{f}+\frac{1}{u}
\frac{1}{v}=\frac{1}{15}-\frac{1}{20}
\frac{1}{v}=\frac{4-3}{60}
v = 60 cm
The image 1 gets formed at 60 cm to ghe right of the lens and it will be inverted.
Therefore, Distance between lens and mirror will be
d = image distance(v) - radius of curvature of convex mirror
s = 60 - 2f
\Rightarrow 2f = 60 - 5
f=\frac{55}{2}=27.5\ cm(convex mirror)
Correct option is 1.