In the nth orbit, the energy of an electron \[{{E}_{n}}=-\frac{13.6}{{{n}^{2}}}eV\]for hydrogen atom. The energy required to take the electron from first orbit to second orbit will be [MP PMT 1987; CPMT 1991, 97; RPMT 1999; DCE 2001; Kerala PMT 2004]

• A.   \[10.2\ eV\]        
• B.   \[12.1\ eV\]
• C.   \[13.6\ eV\]        
• D.   \[3.4\ eV\]