Clock test is a very important part of the competitive exams. And that is why today we have decided to put the emphasis on Clocks and help you with some of the basic concepts and tricks which can be very useful to solve these types of questions.
What is a Clock?
We all know that clock is an instrument used for maintaining and indicating the current time. It usually consists of an hour, minute and a second hand. And that is why the questions asked on clocks are based on these hands and their place only.
The questions that are covered in the clock are based on the angle between their hands and position of these hands. Sometimes the questions are based on the faulty clocks or the time lost and gained by these clocks. We will introduce you to the concepts which will help you solve these types of questions in the exams quickly and effectively. The basics you need to remember in a clock test is every hour has 60 minutes and every minute has 60 seconds. And thus a minute is 1/60th of an hour and a second is 1/60th of a minute.
Learn Calendar Test here in detail.
Concepts for Clock test
When the hands are 15 minutes apart than they are perpendicular to each other. In a clock test, a clock is always circular in shape and it is divided into 60 equal parts i.e. minute spaces. When a minute travels 60 times it takes an hour and it covers 360° of space. And thus a minute covers 6° of space. When the hands in the clock are 30 minutes apart from each other than they are opposite to each other and are in the straight line.
After 1 hour, hour hand travels a space of 5 minutes or 30°. In the clock, hands are 11 times opposite to each other in 12 hours and 22 times opposite in a day. The hands in the clock are perpendicular 22 times in 12 and 44 times in one day. In an hour the minute hand gains 55 minutes over an hour hand. Thus, to calculate the number of minutes gained by the minute over an hour we have to multiply it by (60/55) or (12/11).
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Concepts on Angles
Some of the important concepts that you need to remember before solving the problems on angles are below. In one-minute hour hand travels 0.5°. Minute hand travels 6° per minute. The angle of the hour hand calculated from the vertical is 30n, at any given ‘n’ ‘o’ clock. For further understanding, we will provide you with some solved examples of different types of questions that can be asked in the competitive exams. After that, we will give you some questions for practice.
1. When do the hands of the clock are opposite to each other between 4’O clock and 5’O clock?
A) 33(6/11) over 4’O clock B) 54 (6/11) over 4’O clock
C) 44(6/11) over 4’O clock D) 64 (6/11) over 4’O clock
When the clock is at 4’O clock the minute hand is at 12. To be at opposite hand, minute hand crosses 4 at 20 minutes and after that, it travels for 30 minutes. Thus it gained 20 + 30 = 50 minutes. As mentioned above for one hour of time, minute hand gains 55-minute spaces over an hour hand. Therefore, the total minute spaces that the minute gains for 50 minutes over the hour hand are 50 x (60/55). This is equal to 54 (6/11). Thus the correct answer here is an option (2).
2. Between 8.15 and 7.15 when will the hand of the clock coincide with each other?
A) 30 B) 40
C) 45 D) 60
The formula to solve these type of questions is 60/11 x n. Here n = 8.15 = 8 15/60 = 33/4. Thus 60/11 x 33/4 = 45. Thus the correct answer here is an option (3).
3. In 18 minutes, how much do the minutes gains over the hour hand?
A) 80° B) 90°
C) 99° D) 105°
In an hour, the minute hand gains 330° space over the hour hand which equals to 60 minutes. Thus in 18 minutes, it gains 330°/60 x 18 = 99°. Thus the correct answer here is an option (3).
4. What is the angle between the minute hand and hour hand when the time is 3.25?
A) 47° B) 46°
C) 47 (1/2°) D) 48 (1/2°)
In 12 hours the hour hand forms an angle of 360°. Thus in 3 hours 25 minutes, it traces 360/12 x 41/12 = 102 1/2°. The angle formed by the 25 minutes is 360/60 x 25 = 150°. Thus the total angle formed will 102°/2 x 150° = 47 1°/2. Thus the correct answer here is an option (3).
Study some calendar and clock test practice questions here.
1. When a clock strikes 10 in 27 seconds, it will strike 5 in how many seconds?
A) 12 B) 15
C) 22 D) 20
Ans: The answer is 12.
2. If the hands of the clock coincide every 64 minutes, how much does a watch lose in one day?
A) 96 min B) 34 (5/11)
C) 80 min D) 3
Ans: The answer is 3.
3. How many times do the hands of a clock are perpendicular to each other in a single day?
A) 24 B) 32
C) 42 D) 44
Ans: The answer is 44.