Advertisements
Advertisements
प्रश्न
Write scientific reason.
The sun appears on the western horizon for some time after sunset.
Advertisements
उत्तर
- As ray of light from the Sun enters the earth’s atmosphere, it follows a curved path due to refraction, before reaching the observer.
- This makes the apparent position of the Sun slightly higher than the actual position for the observer.
- Hence, due to the atmospheric refraction of sunlight, the observer on the earth continues to see the setting Sun for two minutes after the Sun has dipped below the horizon, thus delaying the sunset.
APPEARS IN
संबंधित प्रश्न
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.
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?
Write the word AMBULANCE as it would appear when reflected in a plane mirror. Why is it sometimes written in this way (as its mirror image) on the front of an ambulance?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
The angle of reflection is equal to the angle of incidence:
(a) always
(b) sometimes
(c) under special conditions
(d) never
An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the positions of the original and final images seen in the mirror is ______.
Explain how to read the following message which was found on some blotting paper:
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
Fill in the following blank with suitable word:
Light bends when is passes from water into air. We say that it is ............
What is meant by 'refraction of light'? Draw a labelled ray diagram to show the refraction of light.
Light travels more quickly through water than through glass.
Which is optically denser : water or glass?
Name the phenomenon due to which a pencil partly immersed in water and held obliquely appears to be bent at the water surface.
With the help of a diagram, show how when light falls obliquely on the side of a rectangular glass slab, the emergent ray is parallel to the incident ray.
State two factors on which the lateral displacement of the emergent ray depends.
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?
Air is optically .......... than glass.
When a ray of light travels from air to glass, it bends .......... the normal.
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 |
Draw a diagram showing the refraction of a light ray from water to glass. Label on it the incident ray, the angle of incidence (/), and the angle of refraction (r)
A ray of light passes from medium 1 to medium 2. Which of the following quantities of the refracted ray will differ from that of the incident ray: Speed, intensity, frequency, wavelength?
A ray of light A incident from air suffers partial reflection and refraction at the boundary of water.
- Complete the diagram showing (i) the reflected ray B and (ii) the refracted ray C.
- How are the angles of incidence i and refraction r related?
Choose and write the correct option.
If we gradually increase the angle of incidence of a ray of light passing through prism then …..
List in proper sequence the steps of the experiment for determining the approximate focal length of a given concave mirror by obtaining the image of a distant object.
The phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
Light changes its direction when going from one transparent medium to another transparent medium. This is called _______.
Identify the wrong figure from the following.
The incident rays and refracting rays are on opposite sides of the normal.
The speed of light varies in different media.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
Which surface will not reflect most of the light falling on them?
When light passes from one medium to another the ray gets bent. This property of light is called ______.
How does the light travel?
Light travels fastest in a vacuum. Why?
Light is refracted or bent while going from one medium to another because of its ______ changes.
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
A water tank appears shallower when it is viewed from the top due to refraction.
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 |
A ray of light starting from diamond is incident on the interface separating diamond and water. Draw a labelled ray diagram to show. the refraction of light in this case.
