Content Curator
Time can be described as the dimension through which the evolution of any system occurs. It is measured in seconds, minutes, hours, days, weeks, months, and years.
- In both the International System of Units (SI) and the International System of Quantities, time is one of the seven fundamental physical quantities.
- Time is often referred to as periodic events, which are events that repeat themselves after an equal interval of time.
- A simple pendulum or the rotation of an automobile wheel traveling at a constant speed are perfect examples of periodic movements.
- Along with three spatial dimensions, time is commonly referred to as a fourth dimension.
- The measurement of time is called Chronometry.
- The SI unit of time is second and it is defined as the time elapsed between 9192631770 cycles of radiation generated by the transition of two levels of cesium 133 atoms.
Very Short Answers Questions [1 Mark Questions]
Ques. 1 hour is equal to _________ seconds.
- 360
- 600
- 60
- 3600
Ans. The correct answer is d. 3600
Explanation: One hour contains 60 minutes and each minute contains 60 seconds. Therefore 1 hour = 60 x 60 = 3600 seconds
Ques. Which measurement indicates the time?
- Volts
- Years
- Joules
- Watts
Ans. The correct answer is b. Years
Explanation: A year is defined as the time taken by the Earth to complete one rotation around the sun. Therefore years indicate the measurement of time.
Ques. Time was measured by comparing one standard motion, like the movement of the
- Mars
- Asteroid
- Sun
- Venus
Ans. The correct answer is c. Sun
Explanation: The standard motion of the Sun is used as a time reference. Phenomena such as sunset and sunrise are also used as time indicators.
Ques. The occurrence of an event before the given point of time reference is referred to as ______.
- Present
- Past
- Future
- Current
Ans. The correct answer is b. Past
Explanation: Past refers to the occurrence of an event prior to the specified moment in time.
Ques. The SI unit of time is _____.
- Second
- Kilogram
- Watts
- Volts
Ans. The correct answer is a. Second
Explanation: The SI unit of time is Second (s).
Short Answers Questions [2 Marks Questions]
Ques. Define one second.
Ans. One second is defined as the time elapsed between 9192631770 cycles of radiation generated by the transition of two levels of cesium 133 atoms.
Ques. What is the time?
Ans. Time may be described as a continuing and continuous sequence of events that occur in a particular order, from the past through the present to the future. Time is used to quantify, measure, compare, and even sequence occurrences.
Ques. What is a candle clock?
Ans. A candle clock is a thin candle with uniformly spaced markings that, when burning show the passage of time. Candle clocks, while no longer in use today, were an efficient way to check the time indoors, at night, or on a cloudy day.
Ques. What is an atomic clock?
Ans. A clock that measures time by monitoring the resonance frequency of atoms is known as an atomic clock. It is based on atoms with varying energy levels. Electron states in an atom are associated with distinct energy levels, and they interact with a highly specific frequency of electromagnetic radiation during transitions between such states.
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Long Answers Questions [3 Marks Questions]
Ques. How many seconds are there in a year?
Ans. Seconds, minutes, hours, days, weeks, months, and years are the units or terminology used to measure time.
We know
1 minute = 60 seconds
60 minutes = 1 hour
Therefore, 1 hour = 60 x 60 = 3600 seconds
Now, 1 day = 24 hours
Therefore, 1 day = 24 x 3600 seconds = 86400 seconds
Also, 1 year = 365 days
Therefore, 1 year = 365 x 86400 seconds = 31536000 seconds
Hence, There are 31,536,000 seconds
Ques. How has timekeeping changed over time?
Ans. Timekeeping devices have existed since ancient civilizations first noticed celestial bodies as they traveled through the sky. Devices and methods for keeping time have continuously improved as a result of a series of new innovations, beginning with measuring time through continuous processes, such as the flow of liquid in water clocks, progressing to mechanical clocks, and finally repetitive, oscillatory processes, such as the swing of pendulums. All current watches use oscillating timekeepers.
Ques. Why do we need to measure time?
Ans. We must measure time in order to keep track of our everyday activities. For example, scheduling a doctor's appointment, scheduling a meeting with someone, arriving on time at the business, school, or college, and so on, all of these tasks require time measurement.
Very Long Answers Questions [5 Marks Questions]
Ques. What are some ancient time measuring devices?
Ans. Some ancient time measuring devices are
- Sundial: The earliest way of measuring time was used by timekeepers in Ancient Egypt and Sumer around 1500 BC. They utilized the sun's shadow to establish the time. Understanding time does not need any extensive planning or resources. A gnomon, a narrow, angled device, is used to throw a shadow on marks created on a circular plate that indicate the time of day.
- Water clocks: Water clocks were originally stone pots with sloping sides that allowed water to flow down at a consistent pace from a small opening at the base. The pot contains indicators on the inside that indicate the varying water levels as time passes.
- Hourglass: An hourglass was an early instrument used for time measurement. These are also referred to as sandglass or log glass. It consists of two pear-shaped glass bulbs linked at their apexes and separated by a small channel. The bulbs are filled with sand (or, in rare instances, mercury).
Ques. What are some modern time-measuring devices?
Ans. Some modern time-measuring devices are
- Mechanical clocks: Mechanical clocks were far more precise because they employed gears to release energy at regular intervals through a swinging pendulum. Galileo is recognized for inventing the pendulum clock and achieving a remarkable precision of less than one minute per day by utilizing a weighted pendulum.
- Pendulum clock: A pendulum clock keeps time by swinging a weight known as a pendulum. Pendulum clocks must be level and stationary in order to function. Any movement or acceleration will affect the motion of the pendulum, causing it to lose or gain speed and beat.
- Wrist Watches: Over time, the concept moved from public clock towers to individual and personal time-keeping devices. Circular springs that had to be wound once every 24 hours powered wristwatches in the past.
- Atomic clocks: An atomic clock is a precise time measurement apparatus capable of measuring time with extreme accuracy and precision. The atomic clock's normal accuracy is one second per 100 million years.
Ques. How is time measurement done through a Clock?
Ans. A clock is a tool used to measure time. Clocks contain equal-distance markers on a circular surface.
- It is divided into 12 segments, and an hour-long cycle across those 12 segments is regarded as half a day.
- To complete a day, the hour hand circles those 12 parts twice.
- A clock also has minute hands that move around the segments once to complete an hour.
- To complete a minute, the second hand of a clock moves around those segments.
The relationship between time and seconds is as follows:
- 24 hours = 1 day
- 60 minutes = 1 hour
- 60 seconds = 1 minute
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