Question

If two plane mirrors are inclined at an angle theta with horizontal as shown in figure. if a ray incident from 10 degree above horizontal becomes vertical after reflection from this mirror. find theta

Answer 1

Given :

• → Two plane mirrors are inclined at an angle theta with horizontal.

Need To Find :

• → Value of theta (θ)

Required Solution :

☯ The inclination of plane mirror must be (θ), thereafter the Reflected ray will be be (r)

We Know that :

• → r + θ = 90°

Understanding the concept :

☯ Angle of incidence will be (i), then incident from 10° above horizon .

• → 10 + i + i = 90
• → 10 + 2i = 90
• → 2i = 90 - 10
• → 2i = 80
• → i = 80/2
• → i = 40degree

According to Question :

• → r = 40 = 90
• → r = 90 - 40
• → r = 50°

Therefore :

• → The value of [θ] will be 40°

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Answer 2

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \large \sf \blue{Given :}$

Two plane mirrors are inclined at an angle theta with horizontal.

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$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \large\sf \pink{To \: Find :}$

Value of theta (θ)

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$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \large\sf \orange{Solution :}$

The inclination of plane mirror must be (θ), thereafter the Reflected ray will be be (r)

We Know that :

→ r + θ = 90°

Understanding the concept :

Angle of incidence will be (i), then incident from 10° above horizon .

10 + i + i = 90

10 + 2i = 90

2i = 90 - 10

2i = 80

i = 80/2

i = 40degree

According to Question :

r = 40 = 90

r = 90 - 40

r = 50°

Therefore :

The value of [θ] will be 40°

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