In Young's double slit experiment with sodium vapour lamp of wavelength 589 nm and the slits 0.589 mm apart, the half angular width of the central maximum is

• sin^-1 (001)

• sin^-1 (0.0001)

• sin^-1 (0.001)

• sin^-1 (0.1)

A single slit Fraunhofer diffraction pattern is formed with white light. For what wavelength of light the third secondary maximum in the diffraction pattern coincides with the second secondary maximum in the pattern for red light of wavelength 6500 $\stackrel{\circ }{\mathrm{A}}$ ?

• $4400 \stackrel{\circ }{\mathrm{A}}$

• $4100 \stackrel{\circ }{\mathrm{A}}$

• $4642.8 \stackrel{\circ }{\mathrm{A}}$

• $9100 \stackrel{\circ }{\mathrm{A}}$

The head lights of a jeep are 1.2 m apart. If the pupil of the eye of an observer has a diameter of 2 mm and light of wavelength 5896 $\stackrel{\circ }{\mathrm{A}}$ is used, what should be the maximum distance of the jeep from the observer if the two head lights are just separated ?

• 33.9 km

• 33.9 m

• 3.34 km

• 3.39 m

The de-Broglie wavelength of a proton (charge = 1.6 x 10^-19 C, mass = 16 x 10^-27 kg) accelerated through a potential difference of 1 kV is

• $600 \stackrel{\circ }{\mathrm{A}}$

• $0.9 \times {10}^{-12} \mathrm{m}$

• $7 \stackrel{\circ }{\mathrm{A}}$

• 0.9 nm

A radioactive element forms its own isotope after 3 consecutive disintegrations. The particles emitted are

• 3β-particles

• 2β-particles and 1α-particle

• 2β-particles and 1γ-particle

• 2α-particles and 1β-particle

A radioactive substance contains 10000 nuclei and its half-life period is 20 days. The number of nuclei present at the end of 10 days is

• 7070

• 9000

• 8000

• 7500

47.

In Raman effect, Stokes' lines are spectral lines having

• frequency greater than that of the original line

• wavelength equal to that of the original line

• wavelength less than that of the original line

• wavelength greater than that of the original line

The principle of LASER action involves

• amplification of particular frequency emitted by the system

• population inversion

• stimulated emission

• All ofthe above

A ray oflight is travelling from glass to air. (refractive index of glass = 1.5). The angle of incidence is 50°. The deviation of the ray is

• 0°

• 80°

• $50° - {\sin }^{-1} \left[\frac{\sin 50°}{1.5}\right]$

• ${\sin }^{-1} \left[\frac{\sin 50°}{1.5}\right] - 50°$

A vessel of height 2d is half-filled with a liquid of refractive index $\sqrt{2}$ and the other half with a liquid of refractive index n (the given liquids are immiscible). Then the apparent depth of the inner surface of the bottom of the vessel (neglecting the thickness of the bottom of the vessel) will be

• $\frac{\mathrm{n}}{\mathrm{d} \left(\mathrm{n} + \sqrt{2}\right)}$

• $\frac{\mathrm{d} \left(\mathrm{n} + \sqrt{2}\right)}{\mathrm{n}\sqrt{2}}$

• $\frac{\sqrt{2}\mathrm{n}}{\mathrm{d} \left(\mathrm{n} + \sqrt{2}\right)}$

• $\frac{\mathrm{nd}}{\mathrm{d} + \sqrt{2\mathrm{n}}}$