Given:
Number of carbon atoms, N = 2 × 108
Total length = 2.4 cm = 2.4 × 10−2 m
Step 1: Calculate diameter of one carbon atom
Diameter = Total length / Number of atoms
Diameter = (2.4 × 10−2) / (2 × 108)
Diameter = 1.2 × 10−10 m
Step 2: Calculate radius of carbon atom
Radius = Diameter / 2
Radius = (1.2 × 10−10) / 2
Radius = 6.0 × 10−11 m
Step 3: Convert radius into picometres
1 pm = 10−12 m
Radius = 6.0 × 10−11 m = 60 pm
Final Answer:
Radius of carbon atom = 60 pm
Considering Bohr’s atomic model for hydrogen atom :
(A) the energy of H atom in ground state is same as energy of He+ ion in its first excited state.
(B) the energy of H atom in ground state is same as that for Li++ ion in its second excited state.
(C) the energy of H atom in its ground state is same as that of He+ ion for its ground state.
(D) the energy of He+ ion in its first excited state is same as that for Li++ ion in its ground state.