Question

pleasee help by step by step solution ​

Answer 1

Answer:

Given:

Convex mirror is being used.

Size of image is ⅓rd of object size

Focal Length = 40 cm

To find:

Object position

Calculation:

We know the relationship between magnification, object distance, image distance , object height , image height and magnification ;

$\boxed{ \bold{ \dfrac{H_{i}}{H_{o}} = - \dfrac{v}{u} = magnification}}$

$= > \dfrac{1}{3} = - \dfrac{v}{u}$

$= > u = - 3v$

$= > v = - \dfrac{u}{3}$

Now , applying Mirror Formula , we get :

$\bigstar \: \: \dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u}$

$= > \dfrac{1}{40} = - \dfrac{3}{u} + \dfrac{1}{u}$

$= > \dfrac{1}{40} = - \dfrac{2}{u}$

$= > u = - 80 \: cm$

So correct option :

$\boxed{ \red{ \huge{ \bold{Option \: \: 3}}}}$

Answer 2

$\large \underline{ \blue{ \boxed{ \bf \green{Required \: Answer}}}}$

$\large \underline{ \red{ \boxed{ \bf \orange{Question}}}}$

■ Find the position of the object for coves mirror for which size of image is 1/3 of object size (focal length = 40 cm)

$\large \underline{ \blue{ \boxed{ \bf \pink{Answer}}}}$

$<b><marquee behavior="alternate">Option 3 </marquee>$