The extremity of the hour hand of a clock moves `(1//20)^(th)` as the minute hand. If the minute hand is 10 cm long , then the length of the hour hand will be

Options

A. 3 cm
B. 6 cm
C. 12 cm
D. 18 cm

Answer

B

Explanation

`(v_(1))/(v_(2))=(r_(1))/(T_(1))xx(T_(2))/(r_(2))`
`therefore r_(2)=(r_(1).T_(2)v_(2))/(T_(1).v_(1))=(0.1xx12xx1)/(1xx20)=(1.2)/(20)=0.06`
` =6cm`