Distance between object and its image ( magnified by − 3 1 ) is 30 cm. The focal length of the mirror used is ( 4 x ) cm , where magnitude of value of x is _________.

Question

Distance between object and its image ( magnified by − 3 1 ​ ) is 30 cm. The focal length of the mirror used is ( 4 x ​ ) cm , where magnitude of value of x is _________.

TestHub · Accepted Answer

​ M = − 3 1 ​ − − U − V ​ = 3 − 1 ​ ⇒ V = 3 U ​ ​ Distance b / w object and image : ​ U − V = 30 U − 3 μ ​ = 30 ⇒ U = 45 V = 15 f 1 ​ = V 1 ​ + U 1 ​ = − 15 1 ​ − 45 1 ​ ⇒ F = 4 45 ​ x = 45 ​

Physics - Geometrical Optics Question with Solution | TestHub

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JEE Main - 1 year (12th class)