Huygens' wave theory allows us to know the:

When the light diverges from a point source, the shape of the wavefront is:
1. Parabolic.
2. Plane.
3. Spherical.
4. Elliptical.

By Huygen's wave theory of light, we cannot explain the phenomenon of:

Which of the following is not true?

Two superposing waves are represented by the following equations: 
\(y_1=5 \sin 2 \pi(10{t}-0.1 {x}), {y}_2=10 \sin 2 \pi(10{t}-0.1 {x}).\)
Ratio of intensities \(\frac{I_{max}}{I_{min}}\) will be:
1. \(1\)
2. \(9\)
3. \(4\)
4. \(16\)

Two sources with intensity \(I_0\) and \(4I_0\) respectively interfere at a point in a medium. The maximum and the minimum possible intensity respectively would be:
1. \(2I_0, I_0\)
2. \(9I_0, 2I_0\)
3. \(4I_0, I_0\)
4. \(9I_0, I_0\)

Two light sources are said to be coherent when their:

In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is \(\lambda\) is \(K\), (\(\lambda\) being the wavelength of light used). The intensity at a point where the path difference is \(\frac{\lambda}{4}\) will be:
1. \(K\)
2. \(\frac{K}{4}\)
3. \(\frac{K}{2}\)
4. zero

Light waves of intensities \(I\) and \(9I\) interfere to produce a fringe pattern on a screen. The phase difference between the waves at point \(P\) is \(\frac{3\pi}{2}\) and \(2\pi\) at other point \(Q\). The ratio of intensities at \(P\) and \(Q\) is:
1. \(8:5\)
2. \(5:8\)
3. \(1:4\)
4. \(9:1\)