Ray Optics and Optical Instruments Physics - Ray Optics and Optical Instruments

Two unequal resistors are connected in series across a battery. Then the:

The focal length of the objective of a compound microscope is:

A biconvex lens of glass having refractive index 1.47 is immersed in a liquid. It becomes invisible and behaves as a plane glass plate. The refractive index of the liquid is:

Larger aperture of objective lens in an astronomical telescope:

For a glass prism, the angle of minimum deviation will be smallest for the light of:

Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false and R is also false.

Assertion: Endoscopy involves use of optical fibres to study intemal organs.
Reason: Optical fibres are based on phenomena of total internal reflection.

Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false and R is also false.

Assertion: The minimum distance between an object and its real image formed by a convex lens is 2f.
Reason: The distance between an object and its real image is minimum when its magnification is two.

Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false and R is also false.

Assertion: The light travelling from air to glass can not suffer total internal reflection.
Reason: Air is rarer than glass.

Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false and R is also false.

Assertion: The images formed by total intemal reflections are brighter than those formed by mirrors or lenses.
Reason: There is no loss of intensity in total internal reflection.

What is the magnification in this case?

For the telescope described in, what is the separation between the objective lens and the eyepiece?

Define the magnifying power of a compound microscope when the final image is formed at infinity. Why must both the objective and the eyepiece of a compound microscope has short focal lengths? Explain.

Answer the following question:
Magnifying power of a simple microscope is inversely proportional to the focal length of the lens. What then stops us from using a convex lens of smaller and smaller focal length and achieving greater and greater magnifying power?

A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 15 cm thick glass slab held parallel to the table? Refractive index of glass = 1.5. Does the answer depend on the location of the slab?

A screen is placed 90 cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20 cm. Determine the focal length of the lens.

Answer the following question:
The refractive index of diamond is much greater than that of ordinary glass. Is this fact of some use to a diamond cutter?

For a normal eye, the far point is at infinity and the near point of distinct vision is about 25 cm in front of the eye. The cornea of the eye provides a converging power of about 40 dioptres, and the least converging power of the eye-lens behind the cornea is about 20 dioptres. From this rough data estimate the range of accommodation (i.e., the range of converging power of the eye-lens) of a normal eye.

An object AB is kept in front of a concave mirror as shown in the figure.

1. Complete the ray diagram showing the image formation of the object.
2. How will the position and intensity of the image be affected if the lower half of the mirror's reflecting surface is painted black?

1. A mobile phone lies along the principal axis of a concave mirror. Show, with the help of a suitable diagram, the formation of its image. Explain why magnification is not uniform.
2. Suppose the lower half of the concave mirror's reflecting surface is covered with an opaque material. What effect this will have on the image of the object? Explain.

A lady cannot see objects closer than 40cm from the left eye and closer than 100cm from the right eye. While on a mountaineering trip, she is lost from her team. She tries to make an astronomical telscope from her reading glasses to look for her teammates.

1. Which glass should she use as the eyepiece?
2. What magnification can she get with relaxed eye?

The intensity of image ____________ when the lower half part of reflector surface of a concave mirror is covered with an opaque substance