Q.

In series LCR circuit, the capacitance is changed from C to 4C. To keep the resonance frequency unchanged, the new inductance should be          [2024]

1 reduced to L/4  
2 increased by 2L  
3 reduced by L/3  
4 increased to 4L  

Ans.

(1)     

           ω'=ω

           1L'C'=1LCL'C'=LC

           L'(4C)=LC

           L'=L4