Suppose that the lower half of the concave mirror’s reflecting surface in the given figure is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?

A mobile phone lies along the principal axis of a concave mirror, as shown in the figure. Then,

An object is placed at \(10\) cm in front of a concave mirror with a radius of curvature of \(15\) cm. The magnification of the image is:
1. \(-3\)
2. \(3\)
3. \(1\)
4. \(-1\)

An object is placed at \(5\) cm in front of a concave mirror with a radius of curvature of \(15\) cm. The nature of the image is:

Suppose while sitting in a parked car, you notice a jogger approaching towards you in the side view mirror of \(R= 2~\text{m}\). If the jogger is running at a speed of \(5~\text{m/s}\)$$, how fast does the image of the jogger appear to move when the jogger is \(39~\text{m}\) away?
1. \( 5~\text{m/s}\)
2. \(\dfrac{1}{60}~\text{m/s}\)
3. \(\dfrac{1}{280}~\text{m/s}\)
4. \(10~\text{m/s}\)$\mathrm{}$

The earth takes \(24~\text{h}\) to rotate once about its axis. How much time does the sun take to shift by \(1^{\circ}\) when viewed from the earth?
1. \(3~\text{minutes}\)
2. \(2~\text{minutes}\)
3. \(1~\text{minutes}\)
4. \(4~\text{minutes}\)

Light from a point source in the air falls on a convex spherical glass surface (n = 1.5 and radius of curvature = 20 cm) of a glass medium which extends till infinity on other side . The distance of the light source from the glass surface is 100 cm. At what position the image is formed?

A magician during a show makes a glass lens with \(n=1.47\) disappear in a trough of liquid. What is the refractive index of the liquid? 
1. \( 1.47 \)
2. \( 1.33 \)
3. \(0.66 \)
4. \( 1.5\)

If \(f=0.5\) m for a glass lens, what is the power of the lens?
1. \(+0.4\) D
2. \(+4.0\) D
3. \(+0.2\) D
4. \(+2.0\) D

The radii of curvature of the faces of a double convex lens are \(10\) cm and \(15\) cm. Its focal length is \(12\) cm. What is the refractive index of glass?
1. \(1.3\)
2. \(1.2\)
3. \(1.5\)
4. \(1.4\)