Obtain the formulas for the angular width and linear width of the central maximum in a single-slit diffraction experiment.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) The width of the central maximum is defined as the distance between the first minima on either side of the central maximum.
Let the width of the slit be $a$ and the distance between the slit and the screen be $D$.
For the first minimum on one side of the central maximum,the condition for diffraction is given by $a \sin \theta = \lambda$. Since $\theta$ is very small,$\sin \theta \approx \theta$,so $\theta = \frac{\lambda}{a}$.
Here,$\theta$ represents half the angular width of the central maximum.
Therefore,the total angular width of the central maximum is $2\theta = \frac{2\lambda}{a}$.
Now,for the linear width $\beta_0$,we use the relation between arc length,radius,and angle: $\text{arc} = \text{radius} \times \text{angle}$.
Here,the arc length is $\beta_0$,the radius is $D$,and the angle is $2\theta$.
Thus,$\beta_0 = D \times (2\theta) = D \times \frac{2\lambda}{a}$.
Therefore,the linear width of the central maximum is $\beta_0 = \frac{2D\lambda}{a}$.

Explore More

Similar Questions

$A$ screen is placed $50 \, cm$ from a single slit which is illuminated with $6000 \, \mathring{A}$. If the distance between the first and third minima in the diffraction pattern is $3 \, mm$,what is the width of the slit?

Light of wavelength $5000 \, \mathring{A}$ is incident on a single slit such that the angular position of the first minima is $30^\circ$. The width of the slit is:

Difficult
View Solution

$A$ circular disc is placed in front of a narrow source. When the point of observation is $2 \, m$ from the disc,it covers the first $HPZ$. The intensity at this point is $I$. When the point of observation is $25 \, cm$ from the disc,the intensity will be:

Difficult
View Solution

Orange light of wavelength $6000 \times 10^{-10} \ m$ illuminates a single slit of width $0.6 \times 10^{-4} \ m$. The maximum possible number of diffraction minima produced on both sides of the central maximum is $........$

$A$ slit of width $12 \times 10^{-5} \ cm$ is illuminated by monochromatic light of wavelength $6000 \ \mathring A$. Find the half angular width of the central bright maximum in the Fraunhofer diffraction pattern in degrees $(^o)$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo