Define the principal axis of a lens.

A point object O moves from the principal axis of a converging lens in a direction OP. I is the image of O, will move initially in the direction

Convex lens having focal length 25 cm and concave lens having focal length 30 cm are kept in contact, such that they have the same principal axis. Focal length of this combination is ..........

In the figure shown S is a point monochromatic light source of frequency 6xx10^(14)Hz .M is a concave mirror of radius of curvature 20 cm and L is a thin converging lens of focal length 3.75 cm AB is the principal axis of M and L. Light reflected from the mirror and refracted from the lens in succession reaches the screen. An interference pattern is obtained on the screen by this arrangement. Q. If the lens is replaced by another converging lens of focal length (10)/(3)cm and the lens is shifted towards right by 2.5 cm then

In the figure shown S is a point monochromatic light source of frequency 6xx10^(14)Hz .M is a concave mirror of radius of curvature 20 cm and L is a thin converging lens of focal length 3.75 cm AB is the principal axis of M and L. Light reflected from the mirror and refracted from the lens in succession reaches the screen. An interference pattern is obtained on the screen by this arrangement. Q. Distance between two coherent sources whichmakes interference pattern on the screen is

In the figure shown S is a point monochromatic light source of frequency 6xx10^(14)Hz .M is a concave mirror of radius of curvature 20 cm and L is a thin converging lens of focal length 3.75 cm AB is the principal axis of M and L. Light reflected from the mirror and refracted from the lens in succession reaches the screen. An interference pattern is obtained on the screen by this arrangement. Q. Fringe width is

Figure shows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved along the axis until its inverted image is found at the position of the needle. The distance of the needle from the lens is measured to be 45.0 cm. The liquid is removed and the experiment is repeated. The new distance is measured to be 30.0 cm. What is the refractive index of the liquid ?

A thin convex lens of focal length 25 cm is cut into tow pieces 0.5 cm above the principal axis. The top part is placed at (0,0) and an object placed at (-50 cm , 0) Find the coordinates of the image.

Assertion:- If an object placed on the optic axis of a lens is illuminated by white light, then image formed will be coloured and not exactl white. Reason:- The lens has different focal length sfor different colours.

Find the principal values of the following : cosec^(-1)(-1)

Find the principal values of the following : cos^(-1)0