NCERT Class 11 Physics Chapter 1 Units and Measurements Very Short Answer Type Questions Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 19:

Why do we have different units for the same physical quantity?


Magnitude of any given physical quantity may vary over a wide range, therefore, different units of same physical quantity are required.

For example:

1. Mass ranges from (for an electron) to (for the known universe) . We need different units to measure them like milligram, gram, kilogram etc.

2. The length of a pen can be easily measured in cm, the height of a tree can be measured in metres, the distance between two cities can be measured in kilometres and distance between two heavenly bodies can be measured in light year.

Question 20:

The radius of atom is of the order of and radius of nucleus is of the order of fermi. How many magnitudes higher is the volume of atom as compared to the volume of nucleus?


Question 21:

Name the device used for measuring the mass of atoms and molecules.


Mass Spectrograph

Question 22:

Express unified atomic mass unit in kg.


Question 23:

A function f (θ) is defined as:

Why is it necessary for q to be a dimensionless quantity?


Since is a sum of different powers of it has to be dimensionless

Question 24:

Why length, mass and time are chosen as base quantities in mechanics?


Because all other quantities of mechanics can be expressed in terms of length, mass and time through simple relations.


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