Given:
Diameter of carbon atom = 0.15 nm = 0.15 × 10−9 m
Length of scale = 20 cm = 20 × 10−2 m = 0.2 m
Step 1: Write the relation
Number of atoms = Total length / Diameter of one atom
Step 2: Substitute the values
Number of atoms = (0.2) / (0.15 × 10−9)
Number of atoms = (0.2 / 0.15) × 109
Number of atoms = 1.33 × 109
Final Answer:
Number of carbon atoms placed side by side in 20 cm length
= 1.33 × 109 atoms
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.