Question 1 :
The mirror formula is given by<br>$\displaystyle\frac{1}{v}+\displaystyle\frac{1}{u}=\displaystyle\frac{1}{f}$ where the symbols have their usual meanings. Then the lens formula is given by<br>

Question 2 :
Which of the following principles has been followed to propagate light waves through an optical fibre?&nbsp;

Question 3 :
If $I_1$ and $I_2$ be the size of the images respectively for the two positions of lens in the displacement method, then the size of the object is given by

Question 5 :
An air bubble in water shines because of the phenomenon of:

Question 10 :
Optical fibres transmit light along its axis, by the process of :

Question 12 :
State the condition for the following:&#160;<div>A lens has both its focal lengths equal.<br/></div>

Question 13 :
How will the image formed by a convex lens be affected if the&nbsp;central portion of lens is wrapped in black paper ?

Question 15 :
While obtaining the image of a candle by a convex lens, if lower half portion of the lens is blackened to make it opaque completely, then the intensity of the image will be :

Question 16 :
When total internal reflection occurs from&#160;a prism,________of incident light is reflected back to denser medium. Fill on the blank.&#160;

Question 17 :
Playing with a lens one morning, Rita discovers that if she holds the lens 0.120 m away from a wall opposite to a window, she can see a sharp but upside-down picture of the outside world on the wall. That evening, she covers a lighted lamp with a piece of card on which she has pierced a small hole, 0.005 m in diameter. By placing the lens between the illuminated card and the wall, she manages to produce a sharp image of diameter 0.020 m on the wall. What is the distance between the card and the wall?<br><br>

Question 20 :
The light reflected back into the denser medium when a ray of light passes from a denser to a rarer medium,&#160;is said to be ......<br/>

Question 21 :
Which principle is the basis for the transmission of light through fiber optic cables even if the cable is bent?<span><br/></span>

Question 22 :
The distance between a point source of light and a screen which is $60$ $cm$ is increased to 180 cm. The intensity on the screen as compared with the original intensity will be :&nbsp;

Question 24 :
A crack in a glass vessel often shines like a mirror because of&nbsp;

Question 26 :
The image which can not be taken on the screen is called

Question 31 :
The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ........

Question 34 :
The two of the lens above and below axis is made up of two difference materials. A point object is placed on the principle axis of the lens.

Question 35 :
Which of the following is a consequence of total internal reflection?

Question 36 :
When a wave travels from one medium to another, the quantity which will not change is its

Question 37 :
A printed page is seen through a glass slab place on it. The printed words appear raised. This is due to:

Question 39 :
A converging lens is used to form an image on&nbsp;a screen. When the upper half of the lens is&nbsp;covered by an opaque screen.&nbsp;<br>a) Half of the image will disappear<br>b) No part of image will disappear<br>c) Intensity of the image will increase<br>d. Intensity of the image will decrease<br>

Question 40 :
The action of erecting an inverted image without deviation by a prism is used in

Question 42 :
Reflection of light from the surface of separation back into the denser medium is called

Question 44 :
The angle between the two refracting surfaces of a total reflecting prism is :

Question 47 :
When the reflecting or refracting rays do not actually intersect but appear to intersect when produced backwards,&nbsp;

Question 48 :
For which of the following the total internal reflection of light is possible?

Question 49 :
If half part of a convex lens is covered, the focal length _____ change, but the intensity of the image ________.<br/>

Question 50 :
The beautiful natural phenomenon of the rainbow is a combination of which of the following different phenomena?