Measurement Of Time
Chapter Name : Units And Measurements |
Sub Topic Code : 101_11_02_05_01 |
Topic Name : Measurement Of Time |
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Sub Topic Name : Measurement Of Time |
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Introduction
We measure time in seconds which is also its SI unit. Also to measure time, we need a cesium clock which is based on the periodic vibrations produced in a cesium atom.
Pre-Requisites:
Time, Cesium, SI units
Activity:
Defining the SI unit of time which is the second. Understanding what a cesium clock is and what is it based on?
Real Life Question:
How do we decide who is the winner of a race?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Second | The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. |
| Cesium clock | A device used to measure time, which is based on the periodic vibrations produced in a cesium atom. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Stop-watch | Observe how a stop-watch is used to calculate the time taken to complete a race. |
| Speedometer | Observe how a speedometer is used to measure the velocity of the car. |
Real life uses :
Measurement of time is essential because all physical quantities like velocity, speed, power etc are dependent on it.
Places to visit :
Check the laboratory where you may find a cesium clock and understand how it calculates the time.
Practical examples around us
| Examples | Explainations |
|---|---|
| A track event | A track event/race primarily depends on the measurement of time to decide who the winner is. |
What you learn in Theory:
Defining a second and understanding what a cesium clock is.
What you learn in Practice:
Understanding the principle and working of a cesium clock.