Question

the power of concave lens of the focal lenght 150 cm is ?​

Answer 1

Answer:

• -0.66 Dioptre is the required Power of Lens .

Explanation:

Given:-

• Focal length ,f = -150 cm
• Type of Lens = Concave Lens

To Find:-

• Power of Lens ,P

Solution:-

As we know that Power of Lens is defined as the reciprocal of its focal length (in metre) .

• SI unit of Power of Lens is Dioptre.

Conversion of Unit

→ 150 cm = 150/100m = 1.5 m

• P = 1/f

Where

• P denote Power of Lens
• f denote focal length

Substitute the value we get

→ P = -1/.15

→ P = -10/15

→ P = -0.66 D

• Hence, the power of the lens is -0.66 Dioptre

Answer 2

Answer:

Given :-

• Focal length = -150 cm
• Mirror = Concave

To Find :-

Power

Solution :-

As we know that

$\huge \bf \: P = \dfrac1f$

Here,

P is the power

F is the focal length

Firstly let's convert the unit

$\huge \tt \: cm \longrightarrow \:m$

$\tt \: 150 \: cm \: = \dfrac{150}{100} = 1.5 \: m$

$\sf \: P = \dfrac{1}{.15}$

$\sf \: P = \dfrac{ - 10}{15}$

$\frak \green{P = -0.66D}$

Hence :-

The power of Lens at focal length -150 cm and concave mirror is -0.66 Dioptre.