A ray of light is incident on a mirror which is lying on the $$x-y$$ plane. The reflected ray travels along the direction of the vector $$3\hat i-4\hat j+2\hat k.$$ The incident ray must be along:
1.  $$-3\hat i+4\hat j+2\hat k$$
2.  $$3\hat i-4\hat j-2\hat k$$
3.  $$-3\hat i-4\hat j+2\hat k$$
4.  $$-3\hat i+4\hat j-2\hat k$$
Subtopic: Â Reflection at Plane Surface |
From NCERT
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Two plane mirrors are inclined at $$70^\circ.$$ A ray incident on one mirror at an angle, $$\theta$$ after reflection falls on the second mirror and is reflected from there parallel to the first mirror. The value of $$\theta$$ is:
1. $$45^\circ$$
2. $$30^\circ$$
3. $$55^\circ$$
4. $$50^\circ$$
Subtopic: Â Reflection at Plane Surface |
Â 55%
From NCERT
NEET - 2013
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A rod of length $$10~\text{cm}$$ lies along the principal axis of a concave mirror of focal length $$10~\text{cm}$$ in such a way that its end closer to the pole is $$20~\text{cm}$$ away from the mirror. The length of the image is:
1. $$15~\text{cm}$$
2. $$2.5~\text{cm}$$
3. $$5~\text{cm}$$
4. $$10~\text{cm}$$

Subtopic: Â Reflection at Spherical Surface |
Â 67%
From NCERT
AIPMT - 2012
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An object is placed at a distance of $$40$$ cm from a concave mirror of a focal length of $$15$$ cm. If the object is displaced through a distance of $$20$$ cm towards the mirror, the displacement of the image will be:
 1 $$30$$ cm away from the mirror. 2 $$36$$ cm away from the mirror. 3 $$30$$ cm towards the mirror. 4 $$36$$ cm towards the mirror.
Subtopic: Â Reflection at Spherical Surface |
Â 74%
From NCERT
NEET - 2018
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Suppose that the lower half of the concave mirror’s reflecting surface in the given figure is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?

 1 the image will show only half of the object 2 the image will show the whole of the object 3 the intensity of the image will be low 4 both (2) and (3)
Subtopic: Â Reflection at Spherical Surface |
Â 77%
From NCERT
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A light ray falls on a glass surface of refractive index $$\sqrt{3}$$, at an angle of $$60^\circ.$$ The angle between the refracted and reflected rays would be:
 1 $$120^\circ$$ 2 $$30^\circ$$ 3 $$60^\circ$$ 4 $$90^\circ$$
Subtopic: Â Refraction at Plane Surface |
Â 60%
From NCERT
NEET - 2022
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A beam of light is incident vertically on a glass slab of thickness $$1$$ cm, and refractive index $$1.5.$$ A fraction $$A$$ is reflected from the front surface while another fraction $$B$$ enters the slab and emerges after reflection from the back surface. The time delay between them is:

 1 $$10^{-10}$$ s 2 $$5\times 10^{-10}$$ s 3 $$10^{-11}$$ s 4 $$5\times 10^{-11}$$ s
Subtopic: Â Refraction at Plane Surface |
Â 53%
From NCERT
NEET - 2022
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A ray of light $$(1)$$ gets reflected partially at the front surface of a thin film of thickness $$t,$$ and refractive index $$\mu.$$ The reflected ray from the front surface is $$2$$ while that emerging due to reflection from the rear surface is $$3.$$ Assume that ray $$1$$ is incident normally. The optical path difference between rays $$2$$ and $$3$$ is:

1. $$(\mu-1)t$$
2. $$2(\mu-1)t$$
3. $$\mu t$$
4. $$2\mu t$$
Subtopic: Â Refraction at Plane Surface |
From NCERT
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A ray of light passes through three parallel media, with the angles of incidence and emergence as shown in the figure. The refractive indices of the media are $$\mu_{1}$$ = 1, $$\mu_{2}$$ and $$\mu_{3}$$.

Then:
 1 $$\mu_{2}=\frac{1}{3},~\mu_{3}=\frac{1}{2}$$ 2 $$\mu_{2}=3,~\mu_{3}=\frac{3}{2}$$ 3 $$\mu_{2}=\frac{1}{3},~\mu_{3}=\frac{2}{3}$$ 4 $$\mu_{2}=3,~\mu_{3}=2$$
Subtopic: Â Refraction at Plane Surface |
Â 79%
From NCERT