question_answer

Equation of the hour hand at 4 O? clock is

A)            \[x-\sqrt{3}\ y=0\]                   

B)            \[\sqrt{3}\ x-y=0\]

C)            \[x+\sqrt{3}\ y=0\]                 

D)            \[\sqrt{3}\ x+y=0\]

Correct Answer: C

Solution :

           Since the hour, minute and second hands always pass through origin because one end of these hands is always at origin. Now at 4 O? clock, the hour hand makes \[{{30}^{o}}\]angle in fourth quadrant. So the equation of hour hand is \[y=mx\Rightarrow y=-\frac{1}{\sqrt{3}}x\]                               \[\Rightarrow x+\sqrt{3}y=0\].