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प्रश्न
How will you verify the laws of refraction or how the refractive index of glass is determined in the laboratory?
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उत्तर
Place a white sheet of paper on a drawing board. Put a rectangular slab of glass on this white sheet and trace out its boundary ABCD. At any point R on the edge AB, draw a normal NN’. Draw an incident ray PR at any angle say 30°. Fix two pins P1 and P2 vertically on the line PR and at a distance not less than 3 cm from each other. Looking through the other side of the block, fix two pins, P3 and P4 vertically on the white sheet, such that all the four pins P1, P2, P3, and P4 appear to be in a straight line as seen through the glass block. Mark the pinpoints with a fine pencil, remove the block and join the points P3 and P4 by the straight line RS.
PR represents the incident ray and RS represents the refracted ray. ∠PRN and ∠KRN’ are respectively angles of incidence and refraction.
With R as centre and convenient radius, draw a circle cutting the incident ray at Q and the refracted ray at Q’.
From Q and Q’, draw perpendiculars QT and QT’ on the normal NN’
Now sin i = `"QT"/"QR"`
and Sin r = `"Q’T’"/"Q’T’"`
μ = `Sin"i"/Sin"r"="QT"/"QR"."Q’R"/"Q’T’"="QT"/"Q’T’"`
Since QR = Q’R being the radius of the same circle.
Repeat this experiment for other angles of incidence, say 45° and 60°, and find μ.
It is found that for different values of i the ratio.
`sin"i"/Sin"r"` = constant
Thus, it is verified that,
(i) `sin"i"/Sin"r"` is a constant and is equal to aμg.
(ii) The incident the refracted ray and normal line in the same plane.
संबंधित प्रश्न
A student traces the path of a ray of light through a rectangular glass slab for the different values of angle of incidence. He observes all possible precautions at each step of the experiment. At the end of the experiment, on analyzing the measurements, which of the following conclusions is he likely to draw?
(A) ∠i = ∠e < ∠r
(B) ∠i < ∠e < ∠r
(C) ∠i > ∠e > ∠r
(D) ∠i = ∠e > ∠r
Select from the following the best experimental setup for tracing the path of a ray of light passing through a rectangular glass slab.
(a) P
(b) Q
(c) R
(d) S
Draw the diagram given below and clearly show the path taken by the emergent ray.
How must light travel out of a substance if it is not going to be refracted?
When light travels from a rarer to a denser medium, its speed ______.
A ray of light OP passes through a right angles prism as shown in the adjacent diagram.
(a) State the angles of incidence at the faces AC and BC.
(b) Name the phenomenon which the ray suffers at the face AC.
A ray of light passes from water to air. How does the speed of light change?
Why is the colour red used as a sign of danger?
Write a relation between the angle of incidence (i), angle of emergence (e), angle of the prism (A), and angle of deviation (d) for a ray of light passing through an equilateral prism.
The refractive index of air with respect to glass is defined: as gµa = sin i/sin r
Write down a similar expression for aµg in terms of angle i and r.
