An object is placed symmetrically between two plane mirrors inclined at an angle of 72^o, then the total number of images observed is:

(1) 5

(2) 4

(3) 2

(4) Infinite

A person 1.6 m tall is standing at the centre between two walls three metres high. What should be the minimum size of a plane mirror fixed on the wall in front of him if he is to see the full height of the wall behind him?

(1) 0.8 m

(2) 1 m

(3) 1.5 m

(4) 2.3 m

While capturing solar energy for commercial purposes, we use:

(1) Parabolic mirrors

(2) Plane mirrors

(3) Convex mirrors

(4) Concave mirrors

A concave mirror of focal length \(f\) produces an image \(n\) times the size of the object. If the image is real, then the distance of the object from the mirror is:
1. \((n-1)f\)
2. \(\frac{(n-1)}{n}f\)
3. \(\frac{(n+1)}{n}f\)
4. \((n+1)f\)

An object placed in front of a concave mirror of focal length 0.15 m produces a virtual image that is twice the size of the object. The position of the object with respect to the mirror is:

(1) -5.5 cm

(2) -6.5 cm

(3) -7.5 cm

(4) -8.5 cm

When a light ray from a rarer medium is refracted into a denser medium, its:

(1) Speed increases, wavelength increases

(2) Speed decreases, wavelength increases

(3) Speed increases, wavelength decreases

(4) Speed decreases, wavelength decreases

A narrow, paraxial beam of light is converging towards a point I on a screen. A plane plate of glass of thickness t and a refractive index $\mathrm{\mu }$ is introduced in the path of the beam. The convergence point is shifted by:

(1) t (1 - 1/$\mathrm{\mu }$) away

(2) t (1 + 1/$\mathrm{\mu }$) away

(3) t (1 - 1/$\mathrm{\mu }$) nearer

(4) t (1 + 1/$\mathrm{\mu }$) nearer

The length of a vertical pole at the surface of a lake of water $\left(\mu =\frac{4}{3}\right)$ is 24 cm. Then, to an under-water fish just below the water surface, the tip of the pole appears to be:

(1) 18 cm above the surface

(2) 24 cm above the surface

(3) 32 cm above the surface

(4) 36 cm above the surface

A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised by 1 cm. To what depth should water be poured into the beaker so that the coin is again in focus?

(The refractive index of water is $\frac{4}{3}$)

(1) 1 cm

(2) 4/3 cm

(3) 3 cm

(4) 4 cm

Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 x 10⁸ ms^-1 and in medium B is 2.5 x 10⁸ ms^-1. The critical angle for which a ray of light going from A to B suffers total internal reflection is:

(1) sin^-11/2

(2) sin^-12/5

(3) sin^-14/5

(4) sin^-13/4