Question 13
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

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Solution

As per the laws of reflection
The angle of incidence $∠ i = a n g l e o f r e f l e c t i o n ∠ r$
Here as given $∠ i + ∠ r = 90^{\circ}$
$∴ ∠ i + ∠ i = 90^{\circ}$
or $∠ i = \frac{90}{2} = 45^{\circ}$
Hence angle of incidence of a ray = 45 degree

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What is the angle of incidence of a ray if the reflected ray is at an angle of 90 degree to the incident ray?

Q. A light .ray is incident to a plane mirror at an angle of

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(a) While standing before a plane mirror, if you move your right hand to the right, which hand does your image move?
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Question 12

The angle between incident ray and reflected ray is $60^{\circ}$ . What is the value of angle of incidence? Given that, angle of incidence + angle of reflection= $60^{\circ}$ .

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Laws of Reflection

Standard VIII Physics

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Question 13 What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

As per the laws of reflection The angle of incidence ∠i=angle of reflection∠r Here as given ∠i+∠r=90∘ ∴∠i+∠i=90∘ or ∠i=902=45∘ Hence angle of incidence of a ray = 45 degree

Question 13
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

As per the laws of reflection
The angle of incidence $∠ i = a n g l e o f r e f l e c t i o n ∠ r$
Here as given $∠ i + ∠ r = 90^{\circ}$
$∴ ∠ i + ∠ i = 90^{\circ}$
or $∠ i = \frac{90}{2} = 45^{\circ}$
Hence angle of incidence of a ray = 45 degree