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PhysicsGeometrical OpticsRefraction+ReflectionMedium2 minPYQ_2023
PhysicsMediumnumerical

An optical arrangement consists of two concave mirrors M1 and M2, and a convex lens L with a common principal axis, as shown in the figure. The focal length of L is 10 cm. The radii of curvature of M1 and M2 are 20 cm and 24 cm, respectively. The distance between L and M2 is 20 cm. A point object S is placed at the mid-point between L and M2 on the axis. When the distance between L and M1 is n7 cm, one of the images coincides with S. The value of n is _____(Consider the case which gives minimum value).

Question diagram: An optical arrangement consists of two concave mirrors M 1 a
Answer:
80.00
Solution:

For reflection from M2:

Applying mirror formula, we get

1v+1-10=1-12

1v=110-112

v=+60 cm (for I1)

For refraction from L:

Applying lens equation, we get

1v-1u=1f

1v-1-80=110

v=+807 (for I2)

This image should be at focus of M1

 202+807=n7

n=150

Also,

If I2 is formed at pole of M1

then n7=807

n=80

And further if I2 is formed at centre of curvature of M1 then

n7=807+20

 n=220

So value of n can be either 80 or 150 or 220.

Stream:JEE_ADVSubject:PhysicsTopic:Geometrical OpticsSubtopic:Refraction+Reflection
2mℹ️ Source: PYQ_2023

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