Direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by (a is the width of the slit) 

(1) $a\sin \theta =\frac{\lambda }{2}$

(2) $a\cos \theta =\frac{3\lambda }{2}$

(3) $a\sin \theta =\lambda$

(4) $a\sin \theta =\frac{3\lambda }{2}$

A parallel monochromatic beam of light is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first minimum of the diffraction pattern, the phase difference between the rays coming from the edges of the slit is

(1) $0$

(2) $\frac{\pi }{2}$

(3) $\pi$

(4) 2$\pi$

A parallel beam of monochromatic light of wavelength 5000 Å is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to 

(1) 0^o

(2) 15^o

(3) 30^o

(4) 60^o

In the far field diffraction pattern of a single slit under polychromatic illumination, the first minimum with the wavelength ${\lambda }_1$ is found to be coincident with the third maximum at ${\lambda }_2$. So

(1) $3{\lambda }_1=0.3{\lambda }_2$

(2) $3{\lambda }_1={\lambda }_2$

(3) ${\lambda }_1=3.5{\lambda }_2$

(4) $0.3{\lambda }_1=3{\lambda }_2$

A beam of light \(AO\) is incident on a glass slab \((\mu= 1.54)\) in a direction as shown in the figure. The reflected ray \(OB\) is passed through a Nicol prism. On viewing through a Nicole prism, we find on rotating the prism that:

Unpolarized light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam?

$Given:$
$\cos {75}^0 =0.26$
$\cos {57}^0 =0.57$
$\cos {35}^0 =0.82$
$\cos {15}^0 =0.96$
$$

(1) 75°

(2) 55°

(3) 35°

(4) 15°

Unpolarized light of intensity \(32\) Wm^–2 passes through three polarizers such that the transmission axes of the first and second polarizer make an angle of \(30^{\circ}\) with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of the final emerging light will be:
1. \(32\) Wm^–2
2. \(3\) Wm^–2
3. \(8\) Wm^–2
4. \(4\) Wm^–2

When an unpolarized light of intensity \(I_0\) is incident on a polarizing sheet, the intensity of the light which does not get transmitted is:

When the angle of incidence on a material is 60°, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in ms^–1)

1. 3 × 10⁸

2. $\left(\frac{{\displaystyle 3}}{{\displaystyle \sqrt{2}}}\right)\times {10}^8$

3. $\sqrt{3}\times {10}^8$

4. 0.5 × 10⁸