Question 3 :
When a ray of light passes from an optically less dense medium to a more dense medium, it :

Question 4 :
In case of a virtual and erect image, the magnification created by the mirror is

Question 5 :
Which of the following is not an application of convex lens?

Question 6 :
State whether true or false:A concave lens forms a magnified or diminished image depending on the distance of object from it.<br/>

Question 7 :
State whether true or falseA convex mirror is used for obtaining a real and magnified image.

Question 8 :
A convex lens is used to form real image of an object on a screen. It is observed that even when the positions of the object and that screen are fixed are two position of the lens to form real images. If the heights of the images are $$4\ cm$$ and $$9\ cm$$ respectively the height of the object is

Question 9 :
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 10 :
Choose the correct statement(s) related to the motion of object and its image in the case of&#160; mirrors.

Question 12 :
A ray of light travels from air to glass at an angle of incidence of $$37^{\circ}$$, the angle of refraction is $$24^{\circ}$$. What is the refractive index of glass?<br/>(Given: $$\sin 37^{\circ} = 0.60, \sin 24^{\circ} = 0.40)$$

Question 13 :
A real and enlarged image can be obtained by using a:

Question 14 :
The magnification of an image by a convex lens is positive only when the project is placed:

Question 15 :
The maximum magnification that can be obtained with a convex lens of focal length $$2.5\ cm$$ is ( the least distance of distinct vision is $$25\ cm$$)

Question 16 :
Choose the correct answer:<br>The nature of image formed by convex mirror is:

Question 17 :
When a ray of light passes through a rectangular glass slab, the angle of emergence

Question 18 :
A ray of light passes through a glass slab. and the angle of emergence is found smaller than the angle of incidence. So, we may conclude that the glass slab

Question 19 :
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 20 :
The sum of the reciprocals of object distance and image distance is equal to the __________ of a mirror.<br>

Question 21 :
Two thin lenses of focal lengths $$f_{1} and f_{2}$$ are in contact and coaxial. The power of the combination is :<br/>

Question 22 :
The image of an object formed by a device isalways virtual and small. The device may be

Question 23 :
A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens is $$4 D$$, the power of cut lens will be ________.

Question 25 :
When a monochromatic light wave passes from air to glass across a plane surface of separation then:

Question 26 :
To construct a ray diagram, you need a minimum of&#160; _______ ray(s) whose path(s) after refraction through the lens are known.

Question 27 :
A photograph of a horse is taken by a camera whose lens has&#160;been&#160;painted with&#160;black&#160;stripes. The&#160;photograph will be of a :

Question 29 :
A converging lens has a focal length of $$50 cm$$. The power of the lens is

Question 30 :
A straight line passing through the two centres of curvature of lens is called

Question 31 :
A ray of light is incident from one medium $$(\mu = 1.5)$$ into another medium. If the angle of incidence and refraction are, respectively,$$60$$and$$45$$, thenwhatwill be the refractive index of the denser medium?

Question 32 :
Two thin lenses have combined power of $$10\ D$$. When separated by $$20\ cm$$ their equivalent power is $$6.25\ D$$. Their individual powers in $$D$$ are

Question 33 :
The apparent flattening of the sun at sunset and sunrise is due to

Question 34 :
Find out the correct option from the following.<br>(a) The magnification is positive for all virtual images and is negative for all real images.<br>(b) The magnification of concave lens and convex mirror is always positive where as the magnification of convex lens and concave mirror can be positive or negative depending on the position of the object before the lens.<br>

Question 36 :
A student performs an experiment to study the nature of the image formed by a convex lens.&#160;<br/>Arrange the steps in the proper sequence.<br/>(a) Place the lens on a V-shaped stand.<br/>(b) Place the object at $$2F_{1}$$.<br/>(c) Place the object between $$2F_{1}$$ and $$F_{1}$$.<br/>(d) Determine the focal length of the lens by focusing the lens to a distant object like a&#160;tree.<br/>(e) Adjust the position of the screen behind the lens to obtain a clear image and study the nature of the image.<br/>(f) Mark the positions of $$F_{1}, 2F_{1}, F_{2}$$ &#160; and $$ 2F_{2}$$.<br/>(g) Focus the lens to a distant object like a tree.<br/>(h) Place the object just behind $$2F_{1}$$.<br/>(i) Place the object at $$F_{1}$$.<br/>(j) Place the object between $$F_{1}$$ and optic centre of the lens and observe that the image formed is virtual.<br/>

Question 37 :
A thin plane membrane separates hydrogen at27$$^o$$C from hydrogen at 127$$^o$$C, both being at thesame pressure. A plane sound wave enters from the cooler to the hotter side. If the angle of incidenceon the membrane is 30$$^o$$C, then the angle ofrefraction is <br>

Question 38 :
Power of a lens is $$+ 2.0 \mathrm { D }$$then it's focal length is

Question 39 :
For the same statement as above, the ratio of the two image sizes for these two positions of the lens is<br>

Question 40 :
An equiconvex lens is made from glass of refractive index $$1.5$$. If the radius of each surface is changed from $$5 cm$$ to $$6 cm$$, then the power:<br>