Question

if Jagruthi obtained a magnification of -1 with convex lens of focal length 10cm what is the object distance from the lens​

Answer 1

Answer:

A 30 cm tall object is pole 80 cm away from a convex lens of focal length 20 cm .find the position , nature,size and magnification of image

Answer 2

Answer:

-20 cm

Explanation:

m=  v/u……….(1)

Now, for a thin spherical lens,

(1/v)-(1/u)= (1/f)

We multiply this equation by u. This gives

(u/v)-(1)=u/f. But (u/v)=(1/m). Therefore ,

(1/m)-1=u/f OR

(1/m)=(u/f)+1 …..(1)

Now, for convex lens m is negative m=-1.

Putting this value in equation (1), we get

-1= (u/10)+1 OR

u/10 = -2 OR

u= -20 cm.