Solving RLC Circuits: Lamp Glowing & Tuning a 100MHz Circuit

[forevermoreOC]

Hi

I have two probles to tackle on RLC circuits

The first states that if a circuit consists of a lamp (R), variable inductance and fixed capacitor, why does the lamp glow for certain values of L.

Also, you have a tuner at 100mhz, the resistance in the circuit is 15 ohms and inductance 1.50 micro henry's, what capacitance should be used in the circuit?

Any hints would be good
Thanks

 

[Ouabache]

Did you learn about resonance and how that applies to RLC circuits?
If not, that is where I would start. Try to find out what happens to the flow of current
in a circuit as it is brought nearer to resonance.

In your 2nd question, you ask what capacitance should be used. What are you trying to achieve in this case? You may want to find a relationship between the variables you mention.

 

[forevermoreOC]

I found the relationship between the reactive inductance, resistance and the impedance, but when i find the impedance and then try and solve for the reactive capacitance, my reactive capacitance comes out as 0.
Should this happen?