- 1(current)
Q. No.A person can see objects clearly only when they lie between \(50\) cm and \(400\) cm from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use, will be:
| 1. | convex, \(+2.25\) D | 2. | concave, \(-0.25\) D |
| 3. | concave, \(-0.2\) D | 4. | convex, \(+0.5\) D |
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. \(5~\text{cm}\)
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 |
- 1(current)
Q. No.
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