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QJEEM21Ph8cd0: JEE Main 2021 Physics - Class 12 JEEM21Ph8cd0 Solution: An object is placed beyond the centre of curvature C of the…

An object is placed beyond the centre of curvature C of the given concave mirror. If the distance of the object is d1 from C and the distance of the image formed is d2 from C, the radius of curvature of this mirror is :

Multiple Choice Options

  • A 2d1d2d1−d2{{2{d_1}{d_2}} \over {{d_1} - {d_2}}}
  • B 2d1d2d1+d2{{2{d_1}{d_2}} \over {{d_1} + {d_2}}}
  • C d1d2d1+d2{{{d_1}{d_2}} \over {{d_1} + {d_2}}}
  • D d1d2d1−d2{{{d_1}{d_2}} \over {{d_1} - {d_2}}}

Step-by-Step Verified Solution

Using Newton's formula

(f+d1)(f−d2)=f2(f + {d_1})(f - {d_2}) = {f^2}

f2+fd1−fd2−d1d2=f2{f^2} + f{d_1} - f{d_2} - {d_1}{d_2} = {f^2}

f=d1d2d1−d2f = {{{d_1}{d_2}} \over {{d_1} - {d_2}}}

∴\therefore R=2d1d2d1−d2R = {{2{d_1}{d_2}} \over {{d_1} - {d_2}}}

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