Physics - Geometrical Optics Question with Solution | TestHub

PhysicsGeometrical OpticsReflection at curved surfaceMedium2 minPYQ_2021

PhysicsMediumnumerical

The same size images are formed by a convex lens when the object is placed at $20 cm$ or at $10 cm$ from the lens. The focal length of convex lens is

Answer:

15.00

Solution:

$m = \frac{f}{u + f}$

$+ m = \frac{f}{- 10 + f} . . . . (1)$

$- m = \frac{f}{- 20 + f} . . . . . (2)$

$(1) / (2)$

$- 1 = \frac{f - 20}{f - 10}$

$10 - f = f - 20$

$30 = 2 f$

$f = 15 cm$

Stream:JEESubject:PhysicsTopic:Geometrical OpticsSubtopic:Reflection at curved surface

⏱ 2mℹ️ Source: PYQ_2021

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