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# convex mirror

A point object moves towards a convex mirror with a constant speed.Prove that the speed of the image increases as the object comes closer to the mirror.

1 year, 9 months ago

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According to mirror formula
\begin{align}\frac{1}{v}+\frac{1}{u}&=\frac{1}{f}\\\left(\frac{-1}{{v}^2}\right){v}_{i}+\left(\frac{-1}{{u}^2}\right){v}_{o}&=0\\{v}_{i}&=-{\left(\frac{v}{u}\right)}^2{v}_{o}\\\huge\color{blue}{\boxed{{v}_{i}=-{m}^2{v}_{o}}}\end{align} Since magnification of an object approaching towards mirror increases, the speed of image increases. · 1 year, 9 months ago

Thanks a lot! · 1 year, 9 months ago

@Aditya Kumar @Surya Prakash · 1 year, 9 months ago

U just have to differentiate the main equation wrt time. · 1 year, 9 months ago