Question

Two light rays of different wavelengths ${\lambda }_1$ and ${\lambda }_2$ fall respectively, on two glass slabs $S_1$ and $S_2$ normally and come out of the glass slabs simultaneously. If ${\lambda }_1>{\lambda }_2$ and if $t_1$ and $t_2$ are the thickness of the glass slabs $S_1$ and $S_2$ respectively, which among the following is the correct relation between them?

• A. $t_1=t_2$
• B. $t_1<t_2$
• C. $t_1>t_2$
• D. $t_1\ge t_2$

Answer 1

The correct option is C $t_1>t_2$

$v\propto \lambda$

if ${\lambda }_1>{\lambda }_2$

so $v_1>v_2$

And both are coming out in same duration.

$t_1$ and $t_2$are the thickness

So distance $\propto$ velocity

Hence t_1 > t_2

Option 'C' is correct.