A parallel inductor-capacitor circuit has an inductor with an inductance of 25mH and a resistance of 100 ohms and a 10 nF capacitor. If the circuit is supplied by a sinusoidal current source of 5 mA and internal resistance of 10k ohms what is
1. the resonance frequency
2. the bandwidth

 

This page should help you.

http://www.allaboutcircuits.com/vol_2/chpt_6/2.html

 

Equations you'll need:

Resonant frequency fo = 1 / 2π √RL

Bandwidth fw = fo / Q

Where Q = Vc / Vr

Calculate the resonant frequency and use this to calculate the capacitive and inductive reactances. These should be equal at resonant frequency.

Use Ohm's Law to calculate the voltage across each component and then calculate Q, you can use Vc or Vl because they are equal.

Finally shove you answers into the bandwidth equation for the bandwidth frequnecy.

Hope that helps