Download App

Wave Optics — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsWave Optics3 Marks
Question
What is the effect on the interference fringes in Young’s double slit experiment due to each of the following operations? Justify your answers.
  1. The screen is moved away from the plane of the slits.
  2. The separation between slits is increased.
  3. The source slit is moved closer to the plane of double slit.
✓

Answer

  1. Linear fringe width increases $\beta=\frac{\lambda\text{D}}{\text{d}}$
$\Rightarrow\beta\propto\text{D}$

No effect on angular fringe width $\Big(\text{Q}=\frac{\lambda}{\text{d}}\Big).$
  1. Both linear fringe width & angular fringe width decrease $\Big(\beta\propto\frac{1}{\text{d}},\text{Q}\propto\frac{1}{\text{d}}\Big).$
  2. If condition $\frac{\text{s}}{\text{S}}<\frac{\lambda}{\text{d}}$ is satisfied, interference will be obtained otherwise, no interference will be obtained.

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

Explore more

More "3 Marks Question" from Wave Optics→Wave Optics — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Explain the quantisation of angular momentum for an electron orbiting a nucleus.
$\#\#\#$ Write second postulate of Bohr's model and De$-$Broglie's explanation of it.
→
A current loop of arbitrary shape lies in a uniform magnetic field B. Show that the net magnetic force acting on the loop is zero.
→
A rectangular plate of sides a and b is suspended from a ceiling by two parallel strings of length L each figure The separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute simple harmonic motion. Find the time period.
→
A person travels on a spaceship moving at a speed of $\frac{5\text{c}}{13}$
  1. Find the time interval calculated by him between the consecutive birthday celebrations of his friend on the earth.
  2. Find the time interval calculated by the friend on the earth between the consecutive birthday celebrations of the traveller.
→
In a series LCR circuit, $\text{R = 1k}\Omega,\text{C}=2\mu\text{F}$ and voltage across R is 100V. The resonant frequency of the circuit $\omega$ is 200 rad $s^{-1}$. Calculate the value of voltage across L at resonance.
→
Calculate the energy that can be obtained from 1kg of water through the fusion reaction
$^2H + ^2H → ^3H + p.$
Assume that $1.5 \times 10^{-2}%$ of natural water is heavy water $D_2O$ (by number of molecules) and all the deuterium is used for fusion.
→
One end of a cylindrical glass rod $(\mu=1.5)$ of radius 1.0cm is rounded in the shape of a hemisphere. The rod is immersed in water $\Big(\mu=\frac{4}{3}\Big)$ and an object is placed in the water along the axis of the rod at a distance of 8.0cm from the rounded edge. Locate the image of the object.
→
An inductor L of inductance XL is connected in series with a bulb B and an ac source. How would brightness of the bulb change when (i) number of turns in the inductor is reduced, (ii) an iron rod is inserted in the inductor and (iii) a capacitor of reactance $X_C = X_L$ is inserted in series in the circuit. Justify your answer in each case.
→
Which among the curves shown in figure cannot possibly represent electrostatic field lines?
→
  1. Derive the relation between the decay constant and half life of a radioactive substance.
  2. A radioactive element reduces to 25% of its initial mass in 1000 years. Find its half life.
→