(a) While standing before a plane mirror, if you move your right hand to the right, which hand does your image move?
(b) What is the angle of incidence of a ray if the reflected ray is at an angle of 90∘ to the incident ray?
[3 MARKS]
(a) While standing before a plane mirror, if you move your right hand to the right, which hand does your image move?
(b) What is the angle of incidence of a ray if the reflected ray is at an angle of 90∘ to the incident ray?
[3 MARKS]
(a) Answer: 1.5 Marks
(b) Answer with explanation: 1.5 Marks
(a) A mirror image formed by a plane mirror is identical in size and shape but is laterally inverted.
If we move our right hand to the right, our image will move the left hand towards the left. It is because in a plane mirror our "left appears right” and "right appears left”. This is called a lateral inversion.
(b) According to the law of reflection, the angle of incidence is equal to the angle of reflection. If the reflected ray is at an angle of 90∘ to the incident ray, it implies that the reflected ray will be making an angle of 45∘ from the normal. Hence, the angle of reflection is 45∘, therefore the angle of incidence of the ray is 45∘ according to the law of reflection.
(a) Answer: 1.5 Marks
(b) Answer with explanation: 1.5 Marks
(a) A mirror image formed by a plane mirror is identical in size and shape but is laterally inverted.
If we move our right hand to the right, our image will move the left hand towards the left. It is because in a plane mirror our "left appears right” and "right appears left”. This is called a lateral inversion.
(b) According to the law of reflection, the angle of incidence is equal to the angle of reflection. If the reflected ray is at an angle of 90∘ to the incident ray, it implies that the reflected ray will be making an angle of 45∘ from the normal. Hence, the angle of reflection is 45∘, therefore the angle of incidence of the ray is 45∘ according to the law of reflection.
