Light is incident on a glass block as shown in figure. If `theta_(1)` is increased slightly, what happens to `theta_(2)`

Options

A. `theta_(2)` also increases slightly
B. `theta_(2)` is unchanged
C. `theta _(2)` decreases slightly
D. `theta_(2)` changed abruptly, since the ray experiences total internal reflection

Answer

c.

Explanation

As `theta_(1)` increases, `alpha` also inicreases. So, `(90-alpha)` decreases and hence `theta_(2)` decreases.