A diverging lens of focal length 30cm produces an image 20cm from the lens. Determine the object distance

SeyiOlaide

7 years ago

it should be 1/u=1/f - 1/v
the correct answer is 60cm

queensimone1617

2 years ago

f = -30cm

v = -20cm

1/f = 1/u + 1/v

1/-30 = 1/u + 1/(-20)

-1/30 = 1/u - 1/20

Note that 20(image formed) will also take a negative sign because the image formed by a diverging lens(concave) is always VIRTUAL and virtual images are negative.

-1/30 + 1/20 = 1/u

1/u = (-2 + 3)/60

1/u = +1/60

u = +60cm

FGCPOR17576703

3 years ago

the image distance is also meant to be negative

Iphie101

3 years ago

The focal lenght of a diverging lens is always negative.
so if -1/f=1/u plus 1/v
then 1/u=-1/f-1/v
=-1/30-1/20
=-1/12
The reiprocal would be -12cm meaning 12cm on the other side of the lens.

s.samuel

2 years ago

The answer is 60
The focal length and image distance is negative

Levishshhdbdbd

3 years ago

It is meant to be minus

Newton2i

2 years ago

what are you guyssaying the ans is correct you guys should adjust your brain