Q. Equation of the hour hand at 4 O' clock is
Straight Lines
Solution:
Since the hour, minute and second hand always pass through origin because one end of these hands is always at origin. Now at 4 O' clock, the hour hand makes $30^°$ angle in fourth quadrant. So the equation of hour hand is
$y=mx \Rightarrow y=-\frac{1}{\sqrt{3}}x$
$\Rightarrow x+\sqrt{3}y=0$
