An athlete completes one round of a circular track of radius $R$ in $40 \ s$. What will be his displacement at the end of $2 \ min \ 20 \ s$?

$A$ ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster's angle $\phi$. If $\mu$ represents the refractive index of glass with respect to air,then the angle between the reflected and refracted rays is:

$A$ bulb of $100 \ W$ rating is connected with $220 \ V$ supply. The resistance of the bulb is . . . . . . .

The electron affinity of sulfur is ...........

Consider the following statements $A$ and $B$ and identify the correct answer.
$A$. In an elastic collision,if a body suffers a head-on collision with another of the same mass at rest,then the first body comes to rest while the other starts moving with the velocity of the first one.
$B$. Two bodies of equal mass suffering a head-on elastic collision merely exchange their velocities.

The inverse of the point $(1, 2)$ with respect to the circle $x^2 + y^2 - 4x - 6y + 9 = 0$ is