Advertisements
Advertisements
प्रश्न
A man stands 10 m in front of a large plane mirror. How far must the walk before he is 5 m away from his image?
Advertisements
उत्तर
Man should walk 7.5 m towards the mirror.
The reason being, the image formed by a plane mirror is the same distance behind the mirror as it is between the object and the mirror. A distance of 5m between man and his image means that the distance between him and the mirror = `52`= 2.5 m.
Thus, the distance he should walk = 10 - 2.5 = 7.5 m.
APPEARS IN
संबंधित प्रश्न
What is refraction of light?
| 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 |
Name the phenomenon responsible for the following effect:
When we sit in front of a plane mirror and write with our right hand, if appears in the mirror that we are writing with the left hand.
State the uses of plane mirrors.
The figure given alongside shows the image of a clock as seen a plane mirror. The correct time is:
Figure
(a) 2.25
(b) 2.35
(c) 6.45
(d) 9.25
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
Light travels more quickly through water than through glass.
Which is optically denser : water or glass?
A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:
(a) 0°
(b) 45°
(c) 90°
(d) 120°
How does the light have to enter the glass:
to produce a large amount of bending?
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
What is atmospheric reflection? Explain with the help of a labelled diagram that the position of a star as seen by us is not its true position.
A real image is formed by the light rays after reflection or refraction when they:
- actually meet or intersect with each other.
- actually converge at a point.
- appear to meet when they are produced in the backward direction.
- appear to diverge from a point.
Which of the above statements are correct?
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
Observe the given figure and write appropriate phenomenon of light in the box.
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.
The deviation of light ray from its path when it travels from one transparent medium to another transparent medium is called ______.
Which surface will not reflect most of the light falling on them?
The bending of light as it passes from one medium to another is called ______.
Under what circumstances there won’t be any refraction of light when it enters from one medium to another?
