Important Questions of Wave Options in JEE Advanced
FAQs on JEE Advanced Wave Optics Important Questions
1. According to the concepts in chapter Wave Optics, what is Phase Difference and what are the factors that determine it?
Phase difference, put simply is the difference between the phase angle of the two waves. This phase angle is present in the equation of a wave and hence if we know the equations of two waves, we can easily find the phase difference that exists between them. Some factors the phase difference depends upon are: Initial phase difference between the source of the two waves, the refractive index of the medium they are travelling in, presence of any reflections that may or may not take place, the difference in the path lengths of the waves from their respective sources.
2. What do you mean by Wave front and Wave normal after studying the chapter Wave Optics?
The locus of all the points in a given medium that vibrate/oscillate in the same phase is known as a wavefront, while wave normal, like the name suggests, is the perpendicular drawn to the surface of a wavefront at any point, which is same as the direction of propagation of light. A wave normal is nothing more than a simple ray of light. There are different shapes a waveform can have like a spherical, plane, or cylindrical and this shape depends on various factors like the lens used, and the medium.
3. What does the principle of Superposition state and how important is it according to the JEE Advanced exam?
There are plenty of types of questions that can be based upon the principle of superposition and they are often asked in both the main and advanced levels. The principle states that in a given medium, the number of waves travelling simultaneously behaves independently of each other and that the displacement of a particle can be found out at any given instant simply by adding the individual displacements due to all the travelling waves. Students are expected to memorise the displacement equation of a wave to solve the problems quickly and correctly in the exam.
4. Going by the concepts of Wave Optics, what are the important terminologies in Young’s Double Slit Experiment?
Young’s double experiment is one of the most important sub-topics of the Wave Optics chapter and students may pay special attention while studying it since questions can at times get tricky. A brief look at some keywords of the experiment can be listed as:
Coherent sources: Any two sources that have zero (or constant) phase difference between them and that emit a monochromatic light continuously are known as coherent sources.
Fringes: The alternating pattern of bright and dark bands that are produced by the interference of light waves is known as a fringe.
Bright Fringe: The ‘bright’ spots in the fringe bands which are formed by the constructive interference of two superimposing waves are termed as bright fringes.
Dark Fringe: The ‘dark’ spots in the fringe bands which are formed by the destructive interference of two superimposing waves are known as dark fringes.
5. What are some essential formulas to remember in chapter Wave Optics for JEE Advanced?
Wave Optics consist of numerous important laws, principles, derivations and experiments and all of them warrant a huge number of formulas, each consisting of minute details and different cases of its own. We’ve listed some of the most frequently asked ones below:
Displacement equation of a wave: y = R sin 2π/λ (vt+x/2)
Amplitude: R = 2a cos πx/λ
Intensity: I = K4a2 cos2 (πx/λ) (I = KR2)
Condition for Constructive Interference:
Path difference = (2n)λ/2
Phase difference = (2n)π
Condition for Destructive Interference:
Path difference = (2n+1)λ/2
Phase difference = (2n+1)π
YDSE (Young's Double Slit Experiment):
Path difference, x = yd/D
Maxima, y = nλD/d
Here, n = 0,1,2,3….
Minima, y = (2n+1) λD/d
Here, n = 0,1,2,3….
Fringe Width: β = λD/d
Power of Lens: P = 100/f
We’ve hence covered not only some very important questions about wave optics that will help you in your preparation for the JEE Advanced but also some questions that our experts are frequently asked. Visit the Vedantu website for more such topic wise articles that will help strengthen your chances of making it to the IIT. Here’s wishing all the aspirants the best of luck in their endeavor.