Question

25 Marks!!
any physics or science lover ??
I have doubt in this question plzz provide me the correct answer
I want an explanation for the usage of signs
unnecessary answers would b reported!!
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Answer 1

magnification produced (m) =

$\frac{ - v}{u} = \frac{1}{6} \\ where \: v = image \: distance(from \: pole \:of \: mirror) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: u = object \: distance \\ therefore \\ v = \frac{ - u}{6} \\ f = - 6cm \\ using \: mirror \: formula \\ \frac{1}{v} + \frac{1}{u} = \frac{1}{f} \\ \frac{ - 6}{u} + \frac{1}{u} = \frac{ - 1}{6} \\ \frac{ - 5}{u} = \frac{ - 1}{6} \\ u = 30cm\\mark\:it\:as\:brainliest\:if\:u\:find\:it\:helpful$