# If the focal length of the objective lens is increased then the magnifying power of: 1. microscope will increase but that of the 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 |
70%
From NCERT
AIPMT - 2014
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The angle of a prism is $$A$$. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence $$2{A}$$ on the first surface return back through the same path after suffering reflection at the silvered surface. The refractive index $$\mu,$$ of the prism, is:
1. $$2\text{sin}A$$
2. $$2\text{cos}A$$
3. $$\frac{1}{2}\text{cos}A$$
4. $$\text{tan}A$$

Subtopic:  Prisms |
76%
From NCERT
AIPMT - 2014
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A plano-convex lens fits exactly into a plano-concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices $$\mu_1$$ and $$\mu_2$$ and $$R$$ is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is:
 1 $$\dfrac{R}{2(\mu_1-\mu_2)}$$ 2 $$\dfrac{R}{(\mu_1-\mu_2)}$$ 3 $$\dfrac{2R}{(\mu_2-\mu_1)}$$ 4 $$\dfrac{R}{2(\mu_1+\mu_2)}$$
Subtopic:  Lens Makers' Formula |
66%
From NCERT
AIPMT - 2013
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For a normal eye, the cornea of the eye provides a converging power of $$40~\text{D}$$ and the least converging power of the eye lens behind the cornea is $$20~\text{D}$$. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be:
1. $$2.5~\text{cm}$$
2. $$1.67~\text{cm}$$
3. $$1.5~\text{cm}$$
4. $$5~\text{cm}$$

Subtopic:  Human Eye |
62%
From NCERT
AIPMT - 2013
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When a biconvex lens of glass having a refractive index of $$1.47$$ is dipped in a liquid, it acts as a plane sheet of glass. The liquid must have a refractive index:

 1 equal to that of glass. 2 less than one. 3 greater than that of glass. 4 less than that of glass.
Subtopic:  Lens Makers' Formula |
79%
From NCERT
AIPMT - 2012
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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. $$\mu A$$
2. $$\frac{\mu A}{2}$$
3. $$\frac{A}{\mu}$$
4. $$\frac{A}{2\mu}$$

Subtopic:  Prisms |
78%
From NCERT
AIPMT - 2012
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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. $$2f_1+f_2$$
4. $$-2f_1+f_2$$

Subtopic:  Reflection at Spherical Surface |
From NCERT
AIPMT - 2012
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The magnifying power of a telescope is $$9$$. When it is adjusted for parallel rays the distance between the objective and eyepiece is $$20~\text{cm}$$. The focal length of the lenses is:
1. $$10~\text{cm}, ~10~\text{cm}$$
2. $$15~\text{cm}, ~5~\text{cm}$$
3. $$18~\text{cm}, ~2~\text{cm}$$
4. $$11~\text{cm}, ~9~\text{cm}$$

Subtopic:  Telescope |
82%
From NCERT
AIPMT - 2012
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A biconvex lens $$(\mu=1.5)$$  has a radius of curvature of magnitude $$20~\text{cm}$$. Which one of the following options, best describes, the image formed by an object of height $$2$$ cm placed $$30~\text{cm}$$ from the lens?
 1 virtual, upright, height $$=0.5$$ cm 2 real, inverted, height $$=4$$ cm 3 real, inverted, height $$=1$$ cm 4 virtual, upright, height $$=1$$ cm
Subtopic:  Lenses | Lens Makers' Formula | Refraction at Curved Surface |
70%
From NCERT
AIPMT - 2011
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Which of the following is not due to total internal reflection?

 1 Difference between apparent and real depth of the pond 2 Mirage on hot summer days 3 Brilliance of the diamond 4 Working of optical fibre
Subtopic:  Total Internal Reflection |
85%
From NCERT
AIPMT - 2011
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