Question

A mirror has +0.5 m radius of curvature while a lens has -0.1 m focal length. What type of mirror
and lens are these? ​

Answer 1

Given:-

• Radius of Curvature ,R = 0.5m = 50cm

• Focal length of lens ,f = -0.1 m = -10cm

To Find:-

• Which type of lens and mirror

Solution:-

1st condition when mirror have +0.5 or 50 cm

As we know that Relationship between Radius of Curvature and Focal length .

• f = R/2

Where,

f is the focal length

R is the radius of Curvature

Substitute the value we get

→ f = +50/2

→ f = +25 cm

Here, the focal length of mirror is +25 cm so, it is Convex mirror .

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And , it is given that the focal length of the lens is -10 cm or -0.1 m .So , this is concave lens . Because the focal length of Concave Lens is negative .

Answer 2

Answer:

Given :-

• Radius of curvature mirror = +0.5 m
• Lens = -0.1 m

To Find :-

Type of mirror and lens

SoluTion :-

❶ Type of mirror

As it is given that the radius is 0.5 m. So, it can also written as 50 cm.

$\huge \bf \: f \: = \dfrac{R}{2}$

Here,

f = Focal length

R = Radius of curvature mirror

➸ F = 50/2

➸ F = +25 cm

Focal length is +25 cm and it is convec mirror.

❷ Lens

As lens is negative. Therefore, it is concave mirror.