A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is

Question

A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is (A) blue (B) green (C) violet (D) red

Tardigrade Admin · Accepted Answer

Since λr > λg > λb >λv , μr < μg <μb <μr < μv (∵ μ = a + b /λ 2) ∴ vr > vg > vb > vv (∵ v = c/μ). After travelling through the slab, red colour will emerge first because it has largest velocity in slab.

Q. A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is

blue

green

violet

red

Since $λ_{r} > λ_{g} > λ_{b} > λ_{v}, μ_{r} < μ_{g} < μ_{b} < μ_{r} < μ_{v}$
$(∵ μ = a + b / λ^{2})$
$∴ v_{r} > v_{g} > v_{b} > v_{v} (∵ v = c / μ)$ .
After travelling through the slab, red colour will emerge first because it has largest velocity in slab.

Q. A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is

blue

green

violet

red

Since λr​>λg​>λb​>λv​,μr​<μg​<μb​<μr​<μv​ (∵μ=a+b/λ2) ∴vr​>vg​>vb​>vv​(∵v=c/μ). After travelling through the slab, red colour will emerge first because it has largest velocity in slab.

Since $λ_{r} > λ_{g} > λ_{b} > λ_{v}, μ_{r} < μ_{g} < μ_{b} < μ_{r} < μ_{v}$
$(∵ μ = a + b / λ^{2})$
$∴ v_{r} > v_{g} > v_{b} > v_{v} (∵ v = c / μ)$ .
After travelling through the slab, red colour will emerge first because it has largest velocity in slab.