Question

White light is an incident at 20° on a material of silicate flint glass slab as shown. `μ_"violet"` = 1.66 and µ_r = 1.6. For what value of d will the separation be 1 mm in red and violet rays?

 

पर्याय

• `5/3` cm

• `10/3` cm

• 5 cm

• `20/3` cm

Answer 1

`underlinebb(10/3 "cm")`

Explanation:

`sinr_1 = (sin70)/1.66 = 0.9397/1.66`

or `r_1 = 34^circ30^'`

`sinr_2 = sin70/1.6 = 0.9397/1.6`

or `r_2 = 36^circ`

Using `y = (tsin(i - r))/(cosr)`

`y_1 - y_2 = d[(sin(i - r_1))/(cosr_1) - (sin(i - r_2))/(cosr_2)]`

`0.1 = d[(sin35^circ30^')/(cos34^circ30^') - (sin34^circ)/(cos36^circ)]`

or 0.1 = `d[0.5807/0.8241 - 0.5592/0.8090]`

= d[0.71 - 0.68]

or d = `0.1/0.03 = 10/3` cm.