Question

doctor suggested a lens of power -0.5D to a a person , calculate the focal length of lens​

Answer 1

Given:-

• Power of Lens ,P = -0.5 D

To Find:-

• Focal length ,f

Solution:-

According to the Question

We have to calculate the focal length of a lens .

Power of a lens is defined as the reciprocal of focal length (in metres).

• P = 1/f

where,

• P denote Power of lens
• f denote focal length

Substitute the value we get

$:\implies$ -0.5 = 1/f

$:\implies$ f = 1/-0.5

$:\implies$ f = -1/0.5

$:\implies$ f = -10/5

$:\implies$ f = -2m

since the focal length of concave lens is negative .

• Hence, the focal length of the lens is 2m .

Answer 2

Question:-

• Dσctσr ѕuggєѕtєd α lєnѕ σf pσwєr -0.5d tσ α α pєrѕσn , cαlculαtє thє fσcαl lєngth σf lєnѕ.

To Find:-

• Find the focal lens.

Solution:-

First ,

We have to find the focal lens:-

$\dashrightarrow\sf \: P = \dfrac { 1 } { f }$

$\dashrightarrow\sf \: - 0.5 = \dfrac { 1 } { f }$

$\dashrightarrow\sf \: f = - \dfrac { 1 } { 0.5 }$

$\dashrightarrow\sf \: f = - 2 m$

Hence ,

• Thє fσcαl lєngth σf thє lєnѕ íѕ -2 m.