Advertisements
Advertisements
Question
You have learnt in the text how Huygens’ principle leads to the laws of reflection and refraction. Use the same principle to deduce directly that a point object placed in front of a plane mirror produces a virtual image whose distance from the mirror is equal to the object distance from the mirror.
Advertisements
Solution
Let an object at O be placed in front of a plane mirror MO’ at a distance r (as shown in the given figure).
A circle is drawn from the centre (O) such that it just touches the plane mirror at point O’. According to Huygens’ Principle, XY is the wavefront of incident light.
If the mirror is absent, then a similar wavefront X’Y’ (as XY) would form behind O’ at distance r (as shown in the given figure).
X'Y' can be considered as a virtual reflected ray for the plane mirror. Hence, a point object placed in front of the plane mirror produces a virtual image whose distance from the mirror is equal to the object distance (r).
APPEARS IN
RELATED QUESTIONS
Using Huygens's construction of secondary wavelets explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a monochromatic beam of light is incident normally.
State Huygen’s principle.
Use Huygens' principle to verify the laws of refraction.
The refractive indices of water and diamond are `4/3` and 2.42 respectively. Find the speed of light in water and diamond. (c = 3x108 m/s)
Using Huygens’ principle, verify the laws of reflection at a plane surface.
Derive the law of reflection using Huygen’s Wave Theory.
Answer the following question.
Define the term wavefront. Using Huygen's wave theory, verify the law of reflection.
Define a wavefront. Using 'Huygens' principle, draw the shape of a refracted wavefront, when a plane wave is incident on a convex lens.
A plane wave front AB propagating from denser medium (1) into a rarer medium (2) is incident on the surface P1P2 separating the two media as shown in fig.
Using Huygen’s principle, draw the secondary wavelets and obtain the refracted wave front in the diagram.
What is the geometrical shape of the wavefront for:
- Light diverging from a point source?
- The pattern of wavefront of the light from a distant star intercepted by earth?
Answer the following question briefly and to the point:
What is the phase difference between any two points lying on the same wavefront?
Wavefront means
Figure shows a standard two slit arrangement with slits S1, S2, P1, P2 are the two minima points on either side of P (Figure). At P2 on the screen, there is a hole and behind P2 is a second 2-slit arrangement with slits S3, S4 and a second screen behind them.
How is a wavefront different from a ray?
What type of wavefronts are associated with a source infinity?
Represent diagrammatically how the incident planar wavefronts of wavelength λ pass through an aperture of size d, when d is approximately equal to λ.
