Question

an object is kept at a distance of 100cm from lens of power -4 diopter calculate the image distance

Answer 1

u= -100 cm (according to sign convention )
p= -4 (as power is negative so the lens is concave lens, and that's why we took u negative )
p =100/f (because u is given in cm so we use 100/f)
-4=100/f
f= -25 cm
by lens formula
1/f=1/v-1/u
-1/25=1/v -(-1/100)
1/v= -1/25-1/100
1/v= -4-1/100
1/v= -5/100
v= -20 cm

Answer 2

Answer:

u= -100 cm (according to sign convention )

p= -4 (as power is negative so the lens is concave lens, and that's why we took u negative )

p =100/f (because u is given in cm so we use 100/f)

-4=100/f

f= -25 cm

by lens formula

1/f=1/v-1/u

-1/25=1/v -(-1/100)

1/v= -1/25-1/100

1/v= -4-1/100

1/v= -5/100

v= -20 cm

please mark as brainliest!