Question 1 :
The action of erecting an inverted image without deviation by a prism is used in

Question 2 :
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 : 

Question 3 :
A ball coated with lamp black put in a glass&#160;tank containing water appears silvery white due&#160;to :<br/>

Question 4 :
When total internal reflection occurs from&#160;a prism,________of incident light is reflected back to denser medium. Fill on the blank.&#160;

Question 5 :
When a wave travels from one medium to another, the quantity which will not change is its

Question 6 :
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 7 :
How will the image formed by a convex lens be affected if the&nbsp;central portion of lens is wrapped in black paper ?

Question 10 :
The beautiful natural phenomenon of the rainbow is a combination of which of the following different phenomena?

Question 11 :
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 12 :
A crack in a glass vessel often shines like a mirror because of&nbsp;

Question 14 :
State the condition for the following:&#160;<div>A lens has both its focal lengths equal.<br/></div>

Question 16 :
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 17 :
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 19 :
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 20 :
Which of the following is a consequence of total internal reflection?

Question 22 :
The image which can not be taken on the screen is called

Question 25 :
The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ........

Question 28 :
A printed page is seen through a glass slab place on it. The printed words appear raised. This is due to:

Question 31 :
Reflection of light from the surface of separation back into the denser medium is called

Question 36 :
Which of the following principles has been followed to propagate light waves through an optical fibre?&nbsp;

Question 37 :
An endoscope is employed by a physician to&nbsp;view the internal parts of a body organ. It is&nbsp;based on the principle of:

Question 38 :
If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the image

Question 39 :
Can sound undergo total internal reflection at a smooth&nbsp;interface between air and water? If so, in which medium must it be traveling originally?

Question 40 :
The focal length of a glass slab of refractive index $1.5$ is

Question 41 :
The optical path of a monochromatic light is the same if it goes through $2.00$ cm of glass or x cm of ruby. If the refractive index of glass is $1.510$ and that of ruby is $1.760$ find the value of x is _______ cm?

Question 42 :
A glass lens is placed in a medium in which it is found to behave like a glass plate$.$ Refractive index of the medium will be&nbsp;

Question 43 :
A luminous object and a screen are at a fixed distance $D$ apart. A converging lens of focal length $f$ is placed between the object and screen. A real image of the object in formed on the screen for two lens positions if they are separated by a distance $d$ equal to

Question 44 :
(A): Optical fibres are widely used to&#160;communication network.<br/>(R) : Optical fibres are small in size, light weight,&#160;flexible and there is no scope for interference in&#160;them.<br/>

Question 45 :
A concave lens made of water $(\mu = 1.33)$ is placed inside a glass slab $(\mu = 1.5)$ for an object placed between the focus and twice the focus. The image formed is

Question 46 :
A bulb is located on a wall. Its image is to be&#160;obtained on a parallel wall with the help of&#160;convex lens. If the distance between parallel&#160;walls and lens is $'d'$ then, required focal length of lens&#160;placed in between the walls is:<br/>

Question 47 :
An object and a screen are mounted on an optical bench and a converging lens is placed between them so that a sharp image is received on the screen. The linear magnification of the image is $2.5$. The lens is now moved $30\ cm$ nearer the screen and a sharp image is again formed on the screen. The focal length of the lens is:

Question 48 :
A light ray is incident perpendicular to one face of a ${ 90 }^{ \circ&nbsp; }$ prism and is totally internally reflected at the glass-air interface. If the angle of reflection is ${ 45 }^{ \circ&nbsp; }$, we conclude that the refractive index n

Question 49 :
A tower $100 \,m$ tall at a distance of $3 \,km$ is seen through a telescope having objective of focal length $140 \,cm$ and eyepiece of focal length $5 \,cm$. Then the size of final image if it is at $25 \,cm$ from the eye?