Question

47. An object of height 4 cm is kept at a distance of 30 cm from the pole of a 2 diverging mirror. If the focal length of the mirror is 10 cm, the height of the image formed is + 3.0 cm o + 2.5 cm + 1.0 cm (d) +0.75 cm 6. PTO​

Answer 1

Answer:

answer is +1cm

Explanation:

h=4cm

f=-10cm

you can find your answer by lens formula &then use m=v/u

Answer 2

Given :

1. Height of object ( h ) = +4 cm
2. Object distance ( u ) = -30 cm (object since placed on left side of the mirror hence, the distances are taken negative)
3. Focal length of mirror ( f ) = +10 cm

To find :

Height of image formed ( h' )

Explanation :

• In Ray optics, convex mirror is called as a diverging mirror .
• This is because it diverges the ray of light passing through it and hence we consider imaginary extension of the diverging rays .
• Therefore, a convex mirror always forms a virtual image of the object.

Solution :

Step 1

We know,

Mirror formula = $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$

Therefore, $v = \frac{uf}{u-f}$

Substituting the given values in the equation ,

We get, $v = \frac{(-30)(10)}{(-30)-10}$

             $v = \frac{30}{4} = 7.5 cm$

Step 2

Magnification (m) of mirror = $\frac{-v}{u} = \frac{h'}{h}$

Substituting the given values, we get

                                          $m = \frac{-(\frac{15}{2}) }{-30} = \frac{h'}{4}$

Hence, h' = 1 cm

Final answer :

Hence, the height of the image formed will be option (c)1 cm and the image will be virtual and erect and on the backside of the mirror.