Class 9 > Unit 1 Physical Quantities & Measurements > Standard of Length, Mass and Time

 VIDEO LECTURE

THEORY NOTES

Kilogram:

The kilogram is the SI unit of mass and is equal to the mass of the international prototype of

the kilogram, a platinum-iridium standard that is kept at

the International Bureau of Weights and Measures.

1000g = 1kg

1g = 1000mg

1g= 1000000mg

1g=1000000000ng

1g=0.002lb

Meter :

The meter (m) is the SI unit of length and is defined as: The length of the path traveled by light in vacuum during the time interval of 1/299 792 458 of a second. 1000m = 1km 100cm =1m 1cm = 10mm 1inch = 2.53cm 12 inch = 1 ft 1 yard = 3ft

Second:

 Before 1960, the standard of time was defined in terms of the mean solar day for the year 1900. The rotation of the Earth is now known to vary slightly with time, this motion is not a good one to use for defining a time standard. In 1967, the second was redefined to take advantage of the high precision attainable in a device known as an atomic clock,which uses the characteristic frequency of the cesium-133 atom as the “reference clock”. The second is now defined as 9 192 631 770 times the period of vibration of radiation from the cesium atom. 1 hour = 60 min 1 hour = 3600 sec 1min=60sec 1sec=1000ms 1sec=1000000ms

Common Searches

What is the standard unit of length, mass, and time?, What is the standard of mass and time?

What are 7 fundamental quantities?,What are the standards of length mass and time in physics?

Standard of length mass and time ,Standard of length mass and time in physics,Standard of length mass and time formula,Standard of length mass and time example, Standard of length mass and time class 11

Measurement of length mass and time,Mass length time formula, Mass x length time