Q. A beam of light is sent along the line $x - y = 1$. Which after refracting from the $x$-axis entres the opposite side by turning through $30{^\circ}$ towards the normal at the point of incidence on the $x$-axis. Then, the equation of the refracted ray is
A) $\left( 2 - \sqrt{3} \right)x - y = 2 + \sqrt{3}$
B) $\left( 2 + \sqrt{3} \right)x - y = 2 + \sqrt{3}$
C) $\left( 2 - \sqrt{3} \right)x + y = 2 + \sqrt{3}$
D) None of these
Explanation
(d)
From figure refracted ray makes an angle of $75{^\circ}$ with positive direction of $x$-axis and passes through the point (1, 0)
[image:10_image15.emf]
$\therefore$ Its equation is
$(y - 0) = \tan{(45{^\circ}} - 30{^\circ})(x - 1)$
or $y = \left( 2 - \sqrt{3} \right)(x - 1)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.