Question 2 :
Light moves from air into water. The light makes an angle of $47^{\circ}$ with the normal in the air. What angle will it make with the normal in the water?<br>The index of refraction for air is $1.00$.<br>The index of refraction for water is $1.33$

Question 3 :
When the object is at focus of a concave mirror, the image is formed at

Question 5 :
A convex lens makes a real image $4\ cm$ long on a screen. When the lens is shifted to a new position without disturbing the object, we again get a real image on the screen which is $16\ cm$ tall. The length of the object must be

Question 6 :
The frequency of a light wave in a material is $2\times 10^{14} Hz$ and wavelength is $5000\overset {\circ}{A}$. The refractive index of material will be :

Question 7 :
Identify the phenomenon due to which a converging lens forms an image :

Question 8 :
State whether true or false.<br/>A concave mirror always forms erect and diminished images.

Question 10 :
A person uses spectacles of power $+2\ D$. He is suffering from

Question 11 :
A concave lens forms the image of an object which is :<br><br>

Question 13 :
The relation among $u$, $v$ and $f$ for a mirror is:

Question 14 :
The image of an object formed by a device isalways virtual and small. The device may be

Question 15 :
The sum of the reciprocals of object distance and image distance is equal to the __________ of a mirror.<br>

Question 16 :
The radii of curvature of both the sides of a convex lens are $15cm$ and if the refractive index of material of the lens is $1.5$. Then focal length of lens in air is _______cm.

Question 18 :
To construct a ray diagram, you need a minimum of&#160; _______ ray(s) whose path(s) after refraction through the lens are known.

Question 19 :
A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see:

Question 20 :
A ray passing with which part of a lens emerges undeviated ?

Question 21 :
A light ray travels at some angle (not head on) from water in a rectangular aquarium, through the glass side, and out into air . The indices if refraction for water, glass, and air are 1.33, about 1.6, and 1.0, respectively.<br/>Rank the material;s according to the angles of refraction&#160; made by the light ray with the normal in each, greatest first.

Question 22 :
Ratio of the size of the image to the size of the object is known as:

Question 24 :
Four students perform an experiment on tracing the path of a ray of light passing through a rectangular glass slab. Their individual observations are:<br>identify the incorrect observation and correct them.<br>

Question 25 :
The heat of sun focussed by a convex lens on a piece of paper is capable of

Question 26 :
In order to get a diminished virtual image, the object can be placed anywhere in front of a :

Question 27 :
Fill in the blanks:Principal axis is also called ________ of the lens.

Question 29 :
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be<br>

Question 30 :
State whether true or false :&#160;A concave lens will always give a virtual, erect and diminished image.