Question

If the size of the nucleus of an atom is compared with a cricket ball, then the radius of the atom is approximately equal to how many kilometres?
1. 0.5
2. 0.005
3. 5
4. 0.05

Answer 1

Correct Answer - Option 3 : 5

The correct answer is 5.

• Rutherford’s Nuclear Model of Atom proved that most of the space in atoms is generally empty.
• This means the size of the Nucleus is very small in comparison to the total size of an Atom.
• The radius of the atom is about 10^–10 m, while that of the nucleus is 10^–15 m. 
• So, if a cricket ball represents a nucleus, then the radius of an atom would be about 5 km.

As we know the Diameter of the cricket ball(nucleus) is 10 cm.

The size of the Nucleus is about 10^-15 m, while the size of an atom is 10^-10 m.

For 10^-15 size of nucleus → 10^-10 m size of an atom

For 1 m size of Nucleus → (10-10 / 10-15) m size of an atom

100 cm size of Nucleus → 10⁵ m size of an atom

10 cm size of Nucleus(Cricket ball) → 10⁴ m size of an atom

10 cm size of Nucleus(Cricket ball) → 10 km size of an atom    (as 1 km = 1000 m)

but here the radius is asked in the question 

The radius of an atom, so radius = Diameter/2
                                                    =  10/2 km
Therefore, The radius of the atom is approximately equal to 5 km.