Question

.two students A and B observed the image of a candle flame using a spherical lens of focal length 10 cm student a observed and inverted magnified image on the screen placed 25 CM on the other side of the lens and student be observed and inverted image of the same size on the screen what should be their corresponding object distances draw ray diagram to show the image formation by students a and b

Answer 1

Student A:
f=10cms
v=25cm
object distance=?
by lens formula
1/f =1/V- 1/u
1/u = 1/v-1/f
=1/25 -1/10
=2-5/50
=-3/50
u=-50/3
=-16.6cms

student B:
f=10cms
v=20cms
object distance=?
by lens formula
1/f=1/v-1/u
1/u =1/v-1/f
=1/20-1/10
1/u=1-2/20
=-1/20
u= -20cms
object is placed on C and image is formed On C.
refer attachment for ray diagram