Answer
Verified
403.5k+ views
Hint: Path difference is the measure of the path traveled by two waves. It is measured in terms of wavelength \[\lambda \]. If the measure of path difference between two waves is the even integer multiple of \[\lambda \] means, it is called constructive interference. And in turn, if the measure of path difference is the odd multiple integrals of \[\lambda \] means, it is called destructive interference.
Formula used:
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\]
Where,
\[I\]- The intensity at any phase difference \[\phi \]
\[{I_o}\]- Intensity of the light
Complete step by step answer:
(i) Intensity of the central fringe on the screen is given as \[0.1\dfrac{W}{{{m^2}}}\]. The intensity of the fringe can be found by the formula,
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\] --------- (1)
(ii) To find the value of intensity of point at particular path difference, we have to find the intensity of the light \[{I_o}\] and the phase difference \[\phi \]
(iii) Therefore, in case of central fringe, \[I = {I_C}\] and \[\phi = 0\] applying these values in the equation (1)
\[ \Rightarrow {I_C} = 4{I_o}\] \[\left[ {\cos 0 = 1} \right]\]
\[ \Rightarrow {I_o} = \dfrac{{0.1}}{4}\] ---------- (2)
(iv)Finding the phase difference from the path difference by the relation \[\phi = \dfrac{{2\pi }}{\lambda }\Delta x\] Where \[\Delta x\] is the path difference it given here as \[\dfrac{\lambda }{3}\]. Therefore,
\[ \Rightarrow \phi = \dfrac{{2\pi }}{\lambda } \times \dfrac{\lambda }{3}\]
\[ \Rightarrow \phi = \dfrac{{2\pi }}{3}\]
(v) Now we found all the required values. Thus the value of the intensity of the point having path difference \[\dfrac{\lambda }{3}\] is by the equation (1) is,
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\]
\[ \Rightarrow I = 4 \times \dfrac{{0.1}}{4} \times {\cos ^2}\left( {\dfrac{{\tfrac{{2\pi }}{3}}}{2}} \right)\]
\[ \Rightarrow I = 0.1 \times \dfrac{1}{4}\]
\[ \Rightarrow I = 0.025W{m^{ - 2}}\]
\[\therefore I = 2.5mW{m^{ - 2}}\]. Hence the correct option is A.
Note:
The phase difference between the waves can be found by finding the difference between the two-point at a wave. It is the measure of deviation between the two waves. The phase difference between the two waves will be the same if the two waves are moving together. This denotes that the crests of the two waves meet and the troughs too.
Formula used:
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\]
Where,
\[I\]- The intensity at any phase difference \[\phi \]
\[{I_o}\]- Intensity of the light
Complete step by step answer:
(i) Intensity of the central fringe on the screen is given as \[0.1\dfrac{W}{{{m^2}}}\]. The intensity of the fringe can be found by the formula,
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\] --------- (1)
(ii) To find the value of intensity of point at particular path difference, we have to find the intensity of the light \[{I_o}\] and the phase difference \[\phi \]
(iii) Therefore, in case of central fringe, \[I = {I_C}\] and \[\phi = 0\] applying these values in the equation (1)
\[ \Rightarrow {I_C} = 4{I_o}\] \[\left[ {\cos 0 = 1} \right]\]
\[ \Rightarrow {I_o} = \dfrac{{0.1}}{4}\] ---------- (2)
(iv)Finding the phase difference from the path difference by the relation \[\phi = \dfrac{{2\pi }}{\lambda }\Delta x\] Where \[\Delta x\] is the path difference it given here as \[\dfrac{\lambda }{3}\]. Therefore,
\[ \Rightarrow \phi = \dfrac{{2\pi }}{\lambda } \times \dfrac{\lambda }{3}\]
\[ \Rightarrow \phi = \dfrac{{2\pi }}{3}\]
(v) Now we found all the required values. Thus the value of the intensity of the point having path difference \[\dfrac{\lambda }{3}\] is by the equation (1) is,
\[I = 4{I_o}{\cos ^2}\dfrac{\phi }{2}\]
\[ \Rightarrow I = 4 \times \dfrac{{0.1}}{4} \times {\cos ^2}\left( {\dfrac{{\tfrac{{2\pi }}{3}}}{2}} \right)\]
\[ \Rightarrow I = 0.1 \times \dfrac{1}{4}\]
\[ \Rightarrow I = 0.025W{m^{ - 2}}\]
\[\therefore I = 2.5mW{m^{ - 2}}\]. Hence the correct option is A.
Note:
The phase difference between the waves can be found by finding the difference between the two-point at a wave. It is the measure of deviation between the two waves. The phase difference between the two waves will be the same if the two waves are moving together. This denotes that the crests of the two waves meet and the troughs too.
Recently Updated Pages
Classifying Connections: Criteria for Categorizing Individuals You Frequently Encounter
Electrostatic Particle Tracks: Determining Particle Charges and Charge-to-Mass Ratios - Q&A Analysis
The solution to the differential equation x2 y2dx + class 12 mathematical CBSE
Write summary of the poem polonius advice to his son class 12 english CBSE
Write an appreciation on the will to win class 12 english CBSE
What work did the office boy do in the Gemini Studios class 12 english CBSE
Trending doubts
Which are the Top 10 Largest Countries of the World?
Difference Between Plant Cell and Animal Cell
Give 10 examples for herbs , shrubs , climbers , creepers
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Write a letter to the principal requesting him to grant class 10 english CBSE
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
What is the full form of AD a After death b Anno domini class 6 social science CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
Name 10 Living and Non living things class 9 biology CBSE