On superposition of two waves \(y_{1}=3\sin\left ( \omega t-kx \right )\) and \(y_{2}=4\sin\left ( \omega t-kx+\frac{\pi }{2} \right )\) at a point, the amplitude of the resulting wave will be:
1. \(7\)
2. \(5\)
3. \(\sqrt{7}\)
4. \(6.5\)

In Young's double-slit experiment using the light of wavelength \(\lambda\), \(60\) fringes are seen on a screen. If the wavelength of light is decreased by \(50\%\), then the number of fringes on the same screen will be:
1. \(30\)
2. \(60\)
3. \(120\)
4. \(90\)

Five identical polaroids are placed coaxially with \(45^{\circ}\) angular separation between pass axes of adjacent polaroids as shown in the figure. (\(I_0\): Intensity of unpolarized light)
          
The intensity of light, \(I\), emerging out of the \(5\)^th polaroid is:

In Young's double-slit experiment, the ratio of maximum intensity at a point to the intensity at the same point when one slit is closed, is:
1. \(2\)
2. \(3\)
3. \(4\)
4. \(1\)

Two light sources are said to be coherent when their:

Which statement is true for interference?

In Young's double-slit experiment sources of equal intensities are used. The distance between the slits is \(d\) and the wavelength of light used is \(\lambda (\lambda<<d)\). The angular separation of nearest points on either side of central maximum where intensities become half of the maximum value is:
1. \(\frac{\lambda}{d}\)
2. \(\frac{\lambda}{2d}\)
3. \(\frac{\lambda}{4d}\)
4. \(\frac{\lambda}{6d}\)

Four coherent sources of intensity \(I\) are superimposed constructively at a point. The intensity at that point is:
1. \(4I\)
2. \(8I\)
3. \(16I\)
4. \(24I\)