A battery of emf V is connected in series with a resistor of resistance R and an inductor with inductance L and number of turns N as sketched in Figure P21.56. After the current has been fl owing for a long time, the energy stored in the inductor is PE₁.
(a) If R is increased by a factor of two, how does the energy stored in the inductor change? 

(b) If L is decreased by a factor of four, how does the energy stored in the inductor change?
(c) If V is increased by a factor of three, how does the energy stored in the inductor change? 

(d) If the number of turns in the inductor is increased by a factor of two while the length and area of the inductor are kept the same, how does the energy stored in the inductor change? Express your answers as a ratio PE₂/PE₁, where PE₂ is the energy stored in the inductor a long time after the change is made.

 

Transcribed Image Text:

L, N Figure P21.56 ll