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प्रश्न
The figure given alongside shows the image of a clock as seen in a plane mirror. The correct time is:
पर्याय
2.25
2.35
6.45
9.25
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उत्तर
9.25
Explanation:
The image shows a mirror reflection displaying 2:35, which means the left and right sides are reversed. To find the actual time, subtract the reflected time from 11:60 (which represents 12:00). Subtracting 2:35 from 11:60 gives 9:25.
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संबंधित प्रश्न
| Column I | Column II | Column III | |
| 1 | Dispersion | Long-sightedness | Twinkling of stars |
| 2 | Refraction | Splitting of white light into component colours | Convex lens |
| 3 | Hypermetropia | Change in the direction of the ray of light due to change in medium | Spectrum of seven colours |
Fill in the following blank with a suitable word:
When light is reflected, the angles of incidence and reflection are ............ .
A ray of light strikes a plane mirror such that its angle of incidence is 30°. What angle does the reflected ray make with the mirror surface?
The letter F is placed in front of a plane mirror:
- How would its image look like when seen in a plane mirror?
- What is the name of the phenomenon involved?
State the uses of plane mirrors.
The image of an object formed by a plane mirror is:
(a) virtual
(b) real
(c) diminished
(d) upside-down
What is meant by ‘refraction of light’?
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of refraction?
The depth of a pond when seen from above appears to be less.
We can see the sun even when it is little below the horizon because of ______.
The speed of light varies in different media.
Why does a ray of light bend when it travels from one medium to another?
Numerical problems.
The speed of light in water is 2.25 × 108 ms–1. If the speed of light in vacuum is 3 × 108 ms–1, calculate the refractive index of water.
Assertion and reasoning type
- Assertion: If the refractive index of the medium is high (denser medium) the velocity of the light in that medium will be small
- Reason: Refractive index of the medium is inversely proportional to the velocity of the light
A pencil when dipped in water in a glass tumbler appears to be bent at the interface of air and water. Will the pencil appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine. Support your answer with reason.
When light passes from one medium to another the ray gets bent. This property of light is called ______.
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
Match the following:
| Column I | Column II | ||
| 1. | r > 90 | a. | Light gazes at the surface of separation between the two modes. |
| 2. | r = 90 | b. | No refraction. |
| 3. | r < 90 | c. | Refracted ray away from the normal |
According to the first law of refraction, the incident ray, the refracted ray, and the normal at the point of incidence:
