Class 12 ISC Physics Wave Nature of Light Board Questions
Here we provide Class 12 Physics important notes,board questions and predicted questions with Answers for chapter Wave Nature of Light. These important notes,board questions and predicted questions are based on ISC board curriculum and correspond to the most recent Class 12 Physics syllabus. By practising these Class 12 materials, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 12 Board examinations as well as other entrance exams such as NEET and JEE.
class 12 ISC Physics Wave Nature of Light BoardQuestions
Wave Nature of Light BoardQuestions
Q1
Using Huygen’s wave theory derive Snell’s law of refraction
solutions
Given ; According to Huygen principle consider the incident plane wavefront AB on a plane surface
XY, which separates two media 1 and 2. Medium 1 is the rarest of the two, while medium 2 is the
denser of the two. v1 and v2 are the light's velocity in medium 1 and 2, respectively. v1 > v2
solutions
Given ; According to Huygen principle consider the incident plane wavefront AB on a plane surface
XY, which separates two media 1 and 2. Medium 1 is the rarest of the two, while medium 2 is the
denser of the two. v1 and v2 are the light's velocity in medium 1 and 2, respectively. v1 > v2
To prove: Snell's law of refraction
According to consideration diagram is as follow
The wave front first hits point A, then moves on to points B and C. According to Huygen's principle,
secondary wavelets will begin to grow in the second medium with speed v2 from each point of AC. If
the disturbance travels from B to C in time t, then BC=v1t. While the disturbance from
point B reaches point C, the secondary wavelets from point A continue
to travel.
In the second medium, point A must have spread around a hemisphere with a radius of
AD=v2t. The new refracted wave front will be the tangent plane CD traced from point C
over this
hemisphere of radius v2t.
Let i and r be the incidence and refraction angles, respectively.
Snell law has been proved.
Q2
What is the phase difference between any two points lying on the same wavefront?
solutions
solutions
Zero,oscillating in same phase
Q3
With what type of source of light are cylindrical wavefront associated?
solutions
solutions
Line Source
Q5
Derive the law of reflection using Huygens wave theory.
solutions
Given :Consider an obliquely incident plane wave front AB on a plane reflecting surface MM'.
Consider the position when one end A of the wave front touches the mirror at an angle of i while the
other end B still has to travel BC. The time required will be t = BC/ c
solutions
Given :Consider an obliquely incident plane wave front AB on a plane reflecting surface MM'.
Consider the position when one end A of the wave front touches the mirror at an angle of i while the
other end B still has to travel BC. The time required will be t = BC/ c
To prove:
- first law of reflection
- second law of reflection
Prove of first law :According to Huygens' principle, point A begins to produce secondary wavelets,
which will reach a distance of c,t = BC and spread over time t. Draw a circular arc using point A as
the centre and BC as the radius. Draw a tangent CD from point C on this arc. Obviously. The
reflected wave front tilted at an angle r is known as CD. Both the incident and reflected wave
fronts are in the plane of the paper. 1st law of reflection is proved.
The law of reflection using Huygens wave theory has been proved.
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