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Practical Units - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Practical units is considered one of the most asked concept.

  • 16 Questions around this concept.

Solve by difficulty

One solar year is equal to :

 

The time taken by the earth to complete one rotation about its axis with respect to a distant star is called:

 

Which of the following has units of time ?

Which of the following is not a unit for length-

Which of the following is the smallest unit of distance-

Which of the following is a unit of length in the CGS system?

Which of the following is not a unit of time?

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Concepts Covered - 1

Practical units

     

  1. Practical units of  length 

Name

Symbol

Conversion in m

1 fermi   

1 fm

$10^{-15} \mathrm{~m}$ m

1 X-ray unit

1 XU 

$10^{-13} \mathrm{~m}$m

1 Angstrom  

1A^o

$10^{-10} \mathrm{~m}$m

1 micron 

1 \mu m

$10^{-6} \mathrm{~m}$m

1 Astronomical unit

1 AU

$10^{8} \mathrm{~Km}$

1 Light year

1 ly 

$9.46 * 10^{15} \mathrm{~m}$

1 Parsec 

1 Pc

3.26 light year

 

  1. Practical units of mass

 

Name

Symbol

Conversion in kilogram (Kg)

1 Chandra Shekhar Unit

1 CSU

 1.4 times the mass of the sun

1 Metric tonne 

1 Metric tonne 

1000 kg

1 Quintal  

1 Quintal  

100 kg

1 Atomic mass unit

1 amu

$1.67 * 10^{-27} \mathrm{~kg}$

 

  1. Practical units of  Time 

  • - 1 year $=365.25$ days $=3.156 * 10^7$ Sed
    - Lunar Month- 29.53 days ( 29 days 12 hours and 44 minutes) (It is the time taken by the moon to complete 1 revolution around the earth in its orbit or A lunar month is a duration between successive new moons)
    - Solar day-lt is the time taken by the earth to complete one rotation about its axis with respect to Sun.
    - Sidereal day- It is the time taken by the earth to complete one rotation about its axis with respect to a distant star.
    - 1 Solar year- 366.25 sidereal days $=365.25$ average solar day
    - 1 Average Solar Day= $\left(\frac{1}{365.25}^{t h}\right)$ part of the solar year
    - 1 solar second $=\left(\frac{1}{86400}^{t h}\right)_{\text {part of the mean solar day }}$

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Practical units

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