मराठी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान इयत्ता ११

The radius of atom is of the order of 1 Å 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?

Advertisements
Advertisements

प्रश्न

The radius of atom is of the order of 1 Å and the 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?

टीपा लिहा
Advertisements

उत्तर

Radius of atom = 1 Å = 10–10 m

Radius of nucleus = 1 fermi = 1015 m

Volume of atom = VA = `4/3 πR_A^3`

Volume of atom = `4/3 πR_A^3`

Volume of nucleus VN = `4/3 πR_N^3`

`V_A/V_N = (4/3  πR_A^3)/(4/3  πR_N^3)`

= `(R_A/R_N)^3`

= `(10^-10/10^-15)^3`

= 1015

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 2: Units and Measurements - Exercises [पृष्ठ ८]

APPEARS IN

एनसीईआरटी एक्झांप्लर Physics Exemplar [English] Class 11
पाठ 2 Units and Measurements
Exercises | Q 2.20 | पृष्ठ ८

संबंधित प्रश्‍न

The farthest objects in our Universe discovered by modern astronomers are so distant that light emitted by them takes billions of years to reach the Earth. These objects (known as quasars) have many puzzling features, which have not yet been satisfactorily explained. What is the distance in km of a quasar from which light takes 3.0 billion years to reach us?


The principle of ‘parallax’ in section 2.3.1 is used in the determination of distances of very distant stars. The baseline AB is the line joining the Earth’s two locations six months apart in its orbit around the Sun. That is, the baseline is about the diameter of the Earth’s orbit ≈ 3 × 1011m. However, even the nearest stars are so distant that with such a long baseline, they show parallax only of the order of 1” (second) of arc or so. A parsec is a convenient unit of length on the astronomical scale. It is the distance of an object that will show a parallax of 1” (second) of arc from opposite ends of a baseline equal to the distance from the Earth to the Sun. How much is a parsec in terms of meters?


The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show when viewed from two locations of the Earth six months apart in its orbit around the Sun?


Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):

 

the number of strands of hair on your head


Answer the following question.

Star A is farther than star B. Which star will have a large parallax angle?


Ten millimetre makes one centimetre.


Fill in the following chart.

Property Definition Basic Unit Instrument used for measuring
Length      
Mass      
Volume      
Time      

Match the following.

1. Length kelvin
2. Mass metre
3. Time kilogram
4. Temperature second

Now guess the length and width of many other things. Measure and find the difference between your measure and your guess.

Size of Your guess in cm Your measure in cm
  Length Width Length Width
100 Rupee note        
10 Rupee note        
20 Rupee note        
5 Rupee note        
Post card        
Math-Magic book        

How many stamps can be placed along its length?


Can you think of how to cut a postcard so that you can pass through it?


There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.

  • What is the length of the boundary of lake B in the drawing?

Give some examples of larger length measures.


What unit will you use to measure the length of our classroom?


Yard was used as the unit of length.


The SI unit of mass is kg.


  1. The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
  2. Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
  3. From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun-earth diameters.

Mars has approximately half of the earth’s diameter. When it is closest to the earth it is at about 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.


According to the modern definition, what fraction of a second does light travel to define one metre?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×