Ray Optics and Optical Instruments

According to cartesian sign convention, in ray optics

• all distance are taken negative

• all distances in the direction of incident ray are taken positive

• all distances are taken positive

• al distances in the direction of incident ray are taken negative

A linear object of height 10 cm is kept in front of a concave mirror of radius of curvature 15 cm, at a distance of 10 cm. The image formed is

• magnified and erect

• magnified and inverted

• diminished and erect

• diminished and inverted

During scattering of light, the amount of scattering is inversely proportional to ........ of wavelength of light.

• square

• fourth power

• half

• cube

A ray of light travels from an optically denser to a rarer medium. The critical angle for the two media is C. The maximum possible deviation of the ray will be

• 2C

• $\frac{\mathrm{\pi }}{2} - \mathrm{C}$

• $\mathrm{\pi } - \mathrm{C}$

• $\mathrm{\pi } - 2\mathrm{C}$

Light passes successively through two polarimeter tubes each of length 0.29 m. The first tube contains dextro rotatory solution of concentration 60 kgm^-3 and specific rotation 0.01 rad m² kg^-1. The second tube contains laevo rotatory solution of concentration 30 kgm^-5 and specific rotation 0.02 rad m² kg^-1. The net rotation produced is

• 0°

• 15°

• 10°

• 20°

v_o and v_E represent the velocities, ,and μ_E the refractive indices of ordinary and extraordinary rays for a double refracting crystal. Then

• v_o ≤ v_E , μ_o ≤ μ_E, if the crystal is quartz

• v_o ≥ v_E , μ_o ≤ μ_E , if the crystal is calcite

• v_o ≥ v_E , μ_o ≥ μ_E , if the crystal is quartz

• v_o ≤ v_E , μ_o ≥ μ_E , if the crystal is calcite.

The light reflected by a plane mirrormay form a real image

• if the rays incident on the mirror are converging

• if the rays incident on the mirror are diverging

• under no circumstances

• if the object is placed very close to the mirror

A convex is made up of three different materials as shown in the figure. For a point object places on its axis, the number of images formed are

• 5

• 1

• 3

• 4

Light appears to travel in straight lines because

• light consists of very small particles

• the frequency of light is very small

• the velocity of light is different for different colours

• the wavelength of light is very small

An object is placed 12 cm to the left of a converging lens of focal length 8 cm. Another converging lens of 6 cm focal length is placed at a distance of 30 cm to the right of the first lens. The second lens will produce

• a virtual enlarged image

• no image

• a real inverted image

• a real enlarged image