P. 3930. The circuit of a carbon arc lamp is shown in the figure (to ignite the lamp the carbon electrodes are touched together, then they are slowly drawn apart.) The voltage across the gap between the carbon rods as a function of the current can be given by the following formula: , where A and B are constants.
a) If the voltage of the battery U0. can be considered constant what is the resistance of the multiplier Rmax , that should be connected in series to ignite the lamp.
b) Find the stable current if the resistance of the multiplier is R<Rmax .
Data: A=30 V, B=20 W, U0=100 V, R=50 .
Deadline expired on 11 December 2006.