Question

What fraction of a clockwise revolution does the hour hand turn through when it rotates from: [2 MARKS]
a) 3 to 6
b) 6 to 12

Answer 1

Fractions: 1 Mark each

We may observe that in one complete clockwise revolution, the hour hand will rotate through ${360}^{\circ }$
a) We have to find out the fraction of a clockwise revolution that an hour hand turns through when it rotates from 3 to 6.
Now, when the hour hand rotates from 3 to 6 it will rotate through 1 right angle.
$\therefore$ The fraction of revolution = $\frac{{90}^{\circ }}{{360}^{\circ }}$$=$$\frac{1}{4}$ revolution
b) Here the hour hand rotates from 6 to 12, which is to right angles.
$\therefore$ The fraction of revolution = $\frac{{180}^{\circ }}{{360}^{\circ }}$$=$$\frac{1}{2}$ revolution