Question

an object of 2cm high is placed at a distance of 15 cm from a concave lens of focal length 10 cm . find the nature and s8ze of image​

Answer 1

Explanation:

u =15 cm,

f = - 10 cm

so, 1/f = 1/v + 1/u

so, 1/-10 = 1/v + 1/-15

1/v = - 1/10 + 1/15

v = - 30 cm

Now, we know that m(magnefication) is h2/h1

and - v/u in the case of mirror

We have h1 = 2 cm

So, h2/h1 = - v/u

h2/2 = - (-30)/-15

h2 = - 4 cm

Hence the image distance(v) is - 30 cm,

image size (h2) is - 4 cm

And images is real and inverted ( because v is -ve) and bigger than the object :-)