# A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be: 1. 10 cm 2. 15 cm 3. 20 cm 4. 30 cm

Subtopic:  Reflection at Spherical Surface |
61%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A plane mirror is placed horizontally inside water $\left(\mathrm{\mu }=4/3\right)$. A ray falls normally on it. Then the mirror is rotated through an angle $$\theta$$. The minimum value of $$\theta$$ for which the ray does not come out of the water surface is:

1. $\frac{\mathrm{\pi }}{4}$

2. ${\mathrm{sin}}^{-1}\left(\frac{3}{4}\right)$

3. $\frac{1}{2}{\mathrm{sin}}^{-1}\left(\frac{3}{4}\right)$

4. 2${\mathrm{sin}}^{-1}\left(\frac{3}{4}\right)$

Subtopic:  Total Internal Reflection |
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

In an astronomical telescope, the focal length of the objective lens is 100 cm and of the eyepiece is 2 cm. The magnifying power of the telescope for the normal eye is:

1. 50

2. 10

3. 100

4. $\frac{1}{50}$

Subtopic:  Telescope |
89%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal lengths of lenses are:

1. 10 cm, 10 cm

2. 15 cm, 5 cm

3. 18 cm, 2 cm

4. 11 cm, 9 cm

Subtopic:  Telescope |
85%
From NCERT
AIPMT - 2012
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A concave mirror of the focal length ${f}_{1}$ is placed at a distance of d from a convex lens of focal length ${f}_{2}$. A beam of light coming from infinity and falling on this convex lens-concave mirror combination returns to infinity. The distance d must be equal to:

1. ${f}_{1}+{f}_{2}$

2. $-{f}_{1}+{f}_{2}$

3. $2{f}_{1}+{f}_{2}$

4. $-2{f}_{1}+{f}_{2}$

Subtopic:  Refraction at Curved Surface |
From NCERT
AIPMT - 2012
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A ray of light is incident at an angle of incidence, i, on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is $\mu$, the angle of incidence i is nearly equal to:

 1 $$\mu \mathrm{A}$$ 2 $$\frac{\mu A}{2}$$ 3 $$A / \mu$$ 4 $$A / 2 \mu$$
Subtopic:  Prisms |
69%
From NCERT
AIPMT - 2012
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

If the focal length of the objective lens is increased, then magnifying power of:

 1 microscope will increase but that of telescope decrease 2 microscope and telescope both will increase 3 microscope and telescope both will decrease 4 microscope will decrease but that of the telescope will increase
Subtopic:  Simple & Compound Microscope |
67%
From NCERT
AIPMT - 2014
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

An air bubble in a glass slab with refractive index 1.5 (near-normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is:

 1 8 2 10 3 12 4 16
Subtopic:  Refraction at Plane Surface |
74%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

An astronomical refracting telescope will have large angular magnification and high angular resolution when it has an objective lens of:

 1 Small focal length and large diameter 2 Large focal length and small diameter 3 Large focal length and large diameter 4 Small focal length and small diameter

Subtopic:  Telescope |
62%
From NCERT
NEET - 2018
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

For a light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is:

 1 $$30^{\circ}$$ 2 $$45^{\circ}$$ 3 $$60^{\circ}$$ 4 $$90^{\circ}$$
Subtopic:  Refraction at Plane Surface |
58%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints