Clock Introduction:

A Clock is a circular device provided with three hands viz. an hour hand, minute and second hand. The study of the clock is known as “horology”.

[ A basic structure of a clock with three hands ]

Structure of a Clock:

A clock is composed of 360 degrees and divided into 12 equal divisions. The angle between the consecutive divisions is obtained by dividing the total angle of clock 360° by the number of divisions i.e. 12.

[Twelve equal divisions of a clock]

# The angle between any two consecutive divisions = (360°)/12= 30°

[Angle divisions of a clock]

A close observation of a clock reveals that an angular space between any two consecutive divisions has further five more divisions. The area between the two divisions corresponds to a value of 5 minutes. Hence, diving the 30° by five will result in the angular value of a minute.

Angular value of a minute = (30°)/5= 6°

[Angular values of minutes]

The table given below demonstrates the angular values of the first ten minutes:

 Minute(s) Angular values 1 6° 2 12° 3 18° 4 24° 5 30° 6 36° 7 42° 8 48° 9 54° 10 60°

Clocks is easy to learn - You will enjoy it.

Clocks problem classified into four module:

1. Time Angle
2. Angle Time
3. Mirror Time
4. Slow Fast Clocks

Time Angle

1. What is the angle between the hands at 4:12?

A) 55

B) 54

C) 52

D) 56

Explanation: We know for (1hour/60min), Min=360 degree &Hours=30degree.For (1min),Min=6degree,Hour=1/2degree.In 4:12, 4hour 12min is (4*30)+12/2-(12*6)=54degree.

A) 85 degree

B) 90 degree

C) 105 degree

D) 95 degree