Light Questions by Vivek & Soham

A real image is found by the light rays after reflection or refraction when they

• actually meet or intersect with each other

• actually converge at point

• appear to meet when they are produced in the backward direction.

• appear to diverge from a point

A student obtain a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine its focal length.The teacher suggested him to focus distant building about one kilometre far from the laboratory for getting more correct value of the focal length. in order to focus the distant building on the same screen is student should slightly move the :

• mirror away from the screen

• screen away from the mirror

• screen towards the mirror

• screen towards the building

Which of the following can make a parallel beam of flight when light from a point source is incident on it?

• concave mirror as well as convex lens

• convex mirror as well as concave lens

• two plane mirrors placed at 90 degree to each other

• Concave mirror as well as concave lens

A spherical mirror and a spherical lens each have a focal length of -10 cm. The mirror and the lens are likely to be

• both concave

• both convex

• the mirror is concave and the lens is convex

• the mirror is convex and the lens is concave

If the magnification produced by a lens has a negative value, the image will be

• virtual and inverted

• virtual and erect

• real and erect

• real and inverted

Which mirror can produce a virtual, erect and magnified image of an object?

• Concave mirror

• Convex mirror

• Plane mirror

• Both concave and convex mirrors

A light ray enters from medium A to medium B as shown in figure. The

relative refractive index of medium A is to medium B is :

• greater than unity

• less than unity

• equal to unity

• zero

Which of the following statements is true?

• A convex lens has 4 dioptre power having a focal length 0.25 m

• A convex lens has -4 dioptre power having a focal length 0.25m

• A concave lens has 4 dioptre power having a focal length 0.25 m

• A concave lens has -4 dioptre power having a focal length 0.25 m

• a

• c

• d

• b

Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?

• 15 cm in front of the mirror

• 30 cm in front of the mirror

• between 15 cm and and 30 cm in front of the mirror

• more than 30 cm in front of the mirror