Advertisements
Advertisements
प्रश्न
The sun is seen before the sunrise and after the sunset.
Advertisements
उत्तर
EARLY SUNRISE and SUNSET: At sun Rise: When the Sun is just below the horizon, the light from the Sun suffers refraction from RARE to DENSER medium (As the atmosphere is warmer than layers near the earth at that time) bends towards the normal at each refraction. Due to continuous bending of light rays, the Sun can be seen even when its actual position is just below the Horizon. As a result, the Sun is seen in advance, two minutes before it rises above the horizon in the morning.
Similarly, in the evening Sun is seen delayed by 2 minutes longer above the horizon after the Sunset.
APPEARS IN
संबंधित प्रश्न
Explain the following term related to spherical lenses:- aperture
The letter F is placed in front of a plane mirror:
What is the name of the phenomenon involved?
A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?
(A) He should move the mirror away from the screen.
(B) He should move the mirror slightly towards the screen.
(C) He should move the mirror as well as the screen towards the newly selected object.
(D) He should move only the screen towards the newly selected object.
A straight stick partly dipped in water obliquely appears to be bent at the surface of the water.
Select the correct option:
A concave mirror is made by cutting a portion of a hollow glass sphere of radius 30 cm. The focal length of the concave mirror is:
Define the following term in relation to concave mirror.
Principal focus
The following Figure shows a concave mirror MM' on which a ray of light incident from a point P gets reflected to meet the principle axis at O.
(a) Find, by construction, the position of the centre of curvature of the concave mirror.
(b) Write down the value for the radius of curvature of the mirror.
(c) Calculate the focal length of the mirror.
(d ) Which relation is used in deducing the focal length from the radius of curvature?
For a spherical mirror, ______ is true.
A spherical mirror whose reflecting surface is curved outwards is called ______ mirror.
How tall does a mirror have to be to fit an entire person’s body?
