JEE MAIN - Physics (2004 - No. 35)
In a $$LCR$$ circuit capacitance is changed from $$C$$ to $$2$$ $$C$$. For the resonant frequency to remain unchaged, the inductance should be changed from $$L$$ to
$$L/2$$
$$2L$$
$$4L$$
$$L/4$$
解释
For resonant frequency to remain same $$LC$$ should be const. $$LC=$$ const
$$ \Rightarrow LC = L' \times 2C \Rightarrow L' = {L \over 2}$$
$$ \Rightarrow LC = L' \times 2C \Rightarrow L' = {L \over 2}$$