An object is at a distance of \(30\) cm in front of a concave mirror of focal length \(10\) cm. The image of the object will be:

1.	smaller in size.
2.	inverted.
3.	between the focus and centre of curvature.
4.	All of the above.

In normal adjustment, the angular magnification of an astronomical telescope is 39. If the length of the tube is 2 m, then the focal length of the objective and eyepiece are respectively,

(1) 195 cm, 5 cm

(2) 190 cm, 10 cm

(3) 20 cm, 180 cm

(4) 10 cm, 190 cm

The following diagram shows a glass sphere of radius 10 cm with a paraxial incident ray. The refractive index of the material of the glass is

1.  2

2.  1.5

3.  1.75

4.  1.3

A convex lens of focal length 10 cm form real image of an object. The distance between the object and the image may be:

(1) 25 cm

(2) 30 cm

(3) 38 cm

(4) 50 cm

Two plane mirrors are placed perpendicular to each other as shown in the figure. An object O is kept at the angular bisector of the two mirrors. Numbers of images of object O is formed, will be:

1.  4

2.  3

3.  2

4.  1

Two convex lenses of focal lengths 10 cm and 30 cm are kept at a separation of 20 cm. Then the correct statement is:

(1) The effective focal length is 15 cm

(2) Chromatic aberration is minimized

(3) Combination behaves like a convergent lens 

(4) All of these

If one surface of a biconvex lens is silvered, then it behaves as

(1) A concave mirror of focal length $\frac{R}{4\mu -2}$

(2) A concave mirror of focal length $\frac{R}{2\mu }$

(3) A convex mirror of focal length $\frac{R}{4\mu -2}$

(4) A concave mirror of focal length $\frac{R}{2\mu -2}$