In a series $R-L-C$ circuit,the frequency of the source is half of the resonance frequency. The nature of the circuit will be

In a series $LCR$ resonant circuit,the quality factor is measured as $100$. If the inductance is increased by two fold and resistance is decreased by two fold,then the quality factor after this change will be .........

At which point is the circuit inductive?

At an airport,a person is made to walk through the doorway of a metal detector,for security reasons. If she/he is carrying anything made of metal,the metal detector emits a sound. On what principle does this detector work?

For better tuning of a series $LCR$ circuit in a communication system,the preferred combination is

For an $LCR$ series $AC$ circuit, $L = 25 \, mH$, $R = 3 \, \Omega$, and $C = 62.5 \, \mu F$. What is the frequency of the source at which resonance occurs (in $Hz$)?