You are given prism made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prism which will (i) deviate a pencil of white light without much dispersion. (ii) disperse and displace a pencil of white light without much deviation.
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(i) For no dispersion, total angular dispersion produced by two prism should be zero. i.e. `(mu_(b) - mu_( r))A + (mu_(b') - mu_(r ))A' = 0` As `(mu_(b') - mu_( r'))` for flint glass is more than that for crown glass, therefore, `A' lt A` i.e. flint glass prism of smaller angle has to be suitable combined with crown glass prism of larger angle. (ii) For almost no deviation, `(mu_(y) - 1)A + (mu_(y') - 1) A' = 01` Taking crown glass prism if certain angle, we go on increasing angle flint glass prism till this condition is met. In the final combination however, angle of flint glass prism will be smaller than the angle of crown glass prism as `mu_(y')` for flint glass is more than `mu_(y)` for crown glass.
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In dispersion of sunlight by a glass prism, which colour is deviated the most ?
When a ray of sun light passes through the prism each colour of light has its own speed in the glass. The seven colours come out of the prism with different angles of deviation. Red deviates least and violet deviates maximum. Thus a prism can disperse a white light into seven colours which is called colour spectrum. For a thin prism the angle of deviation delta =(n-1) A deviation is given. The angle of dispersion is given as theta = delta v - delta r . The dispersive power is omega = theta / delta mean Using the above ideas give answer the following questions A prism has R.I. for violet and red ” =1.523 n =1.5145 If the angle of prism is A= 2° the dispersive power of the prism is : 0.01639 1.593 0.1639 0.18
When a ray of sun light passes through the prism each colour of light has its own speed in the glass. The seven colours come out of the prism with different angles of deviation. Red deviates least and violet deviates maximum. Thus a prism can disperse a white light into seven colours which is called colour spectrum. For a thin prism the angle of deviation is given as 8 =(n-1) The angle of dispersion is given as 0 = 8 -0. The dispersive power of a prism is 0 mean 8 Using the above ideas give answer the following questions A prism has R.I. for violet and red = 1.523 n = 1.5145. If the angle of prism is A = 2° the dispersive power of the prism is :
When a white light passes through a hollow prism, then there is dispersion but no deviation deviation but no dispersion no dispersion and no deviation dispersion and deviation both
