Question
In a Young's Double slit experiment, first maxima is observed at a fixed point $P$ on the screen. Now the screen is continuously moved away from the plane of slits. The ratio of intensity at point $P$ to the intensity at point $O$ (centre of the screen)

Answer

$I_{p}=\frac{I_{\max }}{2}[1+\cos \phi]=\frac{I_{\max }}{2}\left(1+\cos \frac{2 \pi y}{\beta}\right)$

where $\beta=D \lambda / d$.

First maxima is observed at $P$, i.e., cos. $\frac{2 \pi y}{\beta}$ should be negative. Hence, the ratio

$I_{P} / I_{\max }$ starts decreasing but starts increasing again as cos. $\frac{2 \pi y}{\beta}$ again starts becoming positive.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Two equally charged, identical metal spheres $A$ and $B$ repel each other with a force '$F$'. The spheres are kept fixed with a distance '$r$' between them. A third identical, but uncharged sphere $C$ is brought in contact with $A$ and then placed at the mid-point of the line joining $A$ and $B$. The magnitude of the net electric force on $C$ is
Two circular concentric loops of radii $r_1 = 20\,cm$ and $r_2 = 30\,cm$ are placed in the $X, Y-$ plane as shown in the figure. A current $I = 7\,amp$ is flowing through them. The magnetic moment of this loop system is
The figure shows a man of mass $m$ standing at the end $A$ of a trolley of mass $M$ placed at rest on a smooth horizontal surface. The man starts moving towards the end $B$ with a velocity $u_{rel}$ with respect to the trolley. The length of the trolley is $L$. The distance moved by the man with respect to ground is
The objective and the eyepiece of a microscope have focal lengths of $4\, mm$ and $25\, mm$, respectively. The objective produces a real image $30$ times the size of the object.  The final image is viewed at infinity. The near point of the microscope user is at  $25 \,cm.$ The overall magnification of the microscope is
A prism having an apex angle $4^o$ and refraction index $1.5$ is located in front of a vertical plane mirror as shown in figure. Through what total angle is the ray deviated after reflection from the mirror.....$^o$
A force vector applied on a mass is represented as $\vec F = 6\hat i - 8\hat j + 10\hat k$ and accelerates with $1\;m/{s^2}$. What will be the mass of the body in $kg$.
A copper wire of length $1\, m$ and radius $1\, mm$ is joined in series with an iron wire of length $2\, m$ and radius $3\, mm$ and a current is passed through the wires. The ratio of the current density in the copper and iron wires is
In a diode valve the cathode temperature must be ($\phi$ = work function)
Assertion : Standard optical diffraction gratings can not be used for discriminating between $X-$ ray wavelengths.

Reason : The grating spacing is not of the order of $X-$ ray wavelengths.

An electron in the $n = 1$ orbit of hydrogen atom is bound by $13.6\, eV$ energy is required to ionize it is........$ eV$