Q. No.A student studying the similarities and differences between a camera and the human eye makes the following observations:
(I)
both the eye and the camera have convex lenses.
(II)
in order to focus, the eye lens expands or contracts while the camera lens moves forward or backward.
(III)
the camera lens produces upside-down real images while the eye lens produces only upright real images.
(IV)
a screen in the camera is equivalent to the retina in the eyes.
(V)
a camera adjusts the amount of light entering it by adjusting the aperture of the lens. In the eye, the cornea controls the amount of light.
The correct statements are:
1.
only (I), (II), (IV)
2.
only (I), (III), (V)
3.
only (I), (II), (IV), (V)
4.
all of these
A ray of white light is incident on a spherical water drop whose centre is \(\mathrm{C}\) as shown below. When observed from the opposite side, the emergent light:
| 1. | will be white and will emerge without deviating. |
| 2. | will be internally reflected. |
| 3. | will split into different colours such that the angles of deviation will be different for all colours. |
| 4. | will split into different colours such that the angles of deviation will be the same for all colours. |
A convex lens is used to form an image of an object on a screen. If the upper half of the lens is blackened so that it becomes opaque, then:
| 1. | only half of the image will be visible. |
| 2. | the image position shifts towards the lens. |
| 3. | the image position shifts away from the lens. |
| 4. | the brightness of the image reduces. |
A ray of light is directed toward a corner reflector as shown. The incident ray makes an angle of \(22^\circ\)
| 1. | \(22^\circ\) | 2. | \(68^\circ\) |
| 3. | \(44^\circ\) | 4. | \(34^\circ\) |
A biconvex lens has power \(P.\) It is cut into two symmetrical halves by a plane containing the principal axis. The power of one part will be:
| 1. | \(0\) | 2. | \(\dfrac{P}{2}\) |
| 3. | \(\dfrac{P}{4}\) | 4. | \(P\) |
A ray is incident at an angle of incidence \(i\) on one surface of a small angle prism (with the angle of the prism \(A\)) and emerges normally from the opposite surface. If the refractive index of the material of the prism is \(\mu,\) then the angle of incidence is nearly equal to:
| 1. | \(\dfrac{2A}{\mu}\) | 2. | \(\mu A\) |
| 3. | \(\dfrac{\mu A}{2}\) | 4. | \(\dfrac{A}{2\mu}\) |
Pick the wrong statement in the context with a rainbow.
| 1. | Rainbow is a combined effect of dispersion, refraction, and reflection of sunlight. |
| 2. | When the light rays undergo two internal reflections in a water drop, a secondary rainbow is formed. |
| 3. | The order of colors is reversed in the secondary rainbow. |
| 4. | An observer can see a rainbow when his front is towards the sun. |
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. \(5~\text{cm}\)
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. \(\dfrac{1}{2}\text{cos}A\)
4. \(\text{tan}A\)
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. |
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