Intensity Amplitude Relationship

Q. Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{\pi }{2}$ at point A and $\pi$ at point B. Then, the difference between the resultant intensities at A and B is

1. 2 I
2. 4 I
3. 5 I
4. 7 I

Q.

Two coherent sources of intensity ratio $\beta$ interfere. Find the ratio $\frac{[I_{max}-I_{min}]}{[I_{max}+I_{min}]}$ in the interference pattern.

1. $\frac{2\sqrt{\beta }}{[1+\beta ]}$
2. $\left[\frac{(\sqrt{\beta }+1)}{(\sqrt{\beta }-1)}\right]$
3. $\frac{2\beta }{[1+\beta ]}$

4. $\frac{\sqrt{\beta }}{(1+\sqrt{\beta })}$

Q. Two beams of light having intensities $I$ and $4I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{\pi }{2}$ at point $A$ and $2\pi$ at point $B$. Then the difference between the resultant intensities at $B$ and $A$ will be

1. $4I$
2. $I$
3. $5I$
4. $3I$

Q. The ratio of amplitudes of two waves having same frequency is $3:1$. Find the ratio of maximum and minimum intensities.

Q. Two coherent sources of equal intensities produce a maximum of $100$ units. If the amplitude of one of the sources is reduced by $20$%, then the maximum intensity produced will be:

1. $100$
2. $81$
3. $89$
4. $60$

Q. In a Young's double slit experiment the intensity at a point where the path difference is $\frac{\lambda }{6}$ ($\lambda$ being the wavelength of the light used) is I. If $I_0$ denotes the maximum intensity, $\frac{I}{I_0}$ is equal to

1. $\frac{1}{\sqrt{2}}$
2. $\frac{\sqrt{3}}{2}$
3. $1/2$
4. $3/4$

Q. In a YDSE apparatus, two identical slits are separated by $1$ and distance between the slits and screen is $1m$.The wavelength of light used is $6000A^{\circ }$. The minimum distance between two points on screen having $75\%$ intensity of the maximum intensity is :

1. $0.9$
2. $0.40$
3. $0.30$
4. $0.20$

Q. The optical path difference between the two identical waves arriving at a point $75.5\lambda .$ Is the point bright or dark?

1. bright
2. dark
3. neither bright nor dark
4. none of the above

Q. In Young's double slit experiment, wavelength of light is $6000\mathring{A}$. Then the phase difference between the light waves reaching the third bright fringe from the central fringe will be:

1. zero
2. $2\pi$
3. $4\pi$
4. $6\pi$

Q. Light of wavelength 583.3 nm is incident normally on the slit of width 0.1 mm. What will be the angular width of the central diffraction maximum at a distance of 1m from the slit in degrees

1. 0.68
2. 1.02
3. 0.34
4. None of these