A ray of light propagating along the direction $\frac{1}{2}(\widehat{i}+\sqrt{3}\widehat{j})\backslash frac12(\backslash hat\; i+\backslash sqrt\{3\}\backslash hat\; j)$ is incident on a plane mirror. After reflection, it moves along the direction $\frac{1}{2}(\widehat{i}-\sqrt{3}\widehat{j})\backslash frac12(\backslash hat\; i-\backslash sqrt\{3\}\backslash hat\; j)$. The angle of incident is

A spherical lens forms an image, twice the length of the object, on a screen. The distance between the object and the screen is 120 cm. The power of the lens, is (nearly)

The focal length, of a thin biconvex lens, is 20 cm. When an object is moved from a distance of 25 cm in front of it to 50 cm, the magnification of its image changes is $m_{1}m\_1$ to $m_{2}m\_2$. The ratio $(\frac{m_1}{m_2})(\backslash frac\{m\_1\}\{m\_2\})$ is

A convex lens is in contact with a concave lens. The magnitude, of the ratio of their focal lengths, is $\left(\frac{2}{3}\right)\backslash left(\backslash frac23\backslash right)$. Their equivalent focal length is 30 cm. The individual focal lengths (in cm), of the two lenses, are, respectively,

An observer looks at a distant tree of height 10 cm, with a telescope of magnifying power 20. To the observer, the tree would appears.

In a Young’s double slit experiment, using monochromatic light of wavelength $\lambda \backslash lambda$ , the path difference (in terms of integer n), corresponding to a point, having half the peak intensity, is

A beam consists of an unpolarised and a plane-polarised part. The beam is viewed through a polarised. On rotating the polaroid through one full circle, about the direction of propagation of the beam as axis, the intensity of the transmitted light.

The headlights of a car are 1.2 m apart. They emit light of $\lambda =600\backslash lambda\; =\; 600$ nm. The diameter of the pupil of the observer's eye is 3 mm. The maximum distance of car from observer so that the two headlights are just resolved is

A beam of unpolarised light, of intensity $I_{0}I\_0$, is passed through a polaroid A. It is next passed through another polaroid, B, which is oriented so that its principal plane makes an angle of $45^{\circ }45^\backslash circ$, relative to that of A. The intensity of emergent light is

A ray of green light is incident from water to air; (at the air-water interface) at the critical angle of incidence. Select the correct statement: