Question

At what time can the hour hand and the minute hand be perpendicular to each other?

• A. 09:00
• B. 06:15
• C. 03:45
• D. Both A & B

Answer 1

The correct option is A

09:00

At $09:00$, hour hand and minute hand are at right angles to each other. At all the other instants, the minute hand has moved, so hour hand would have moved too. So, the angle cannot be ${90}^{\circ }$ in those cases.