A proton is moving at 3.00x10^5 m/s in the positive x direction. A magnetic field of 0.800 T is in the positive z direction. What is the magnitude and direction of magntic force on the proton?
An 8.00-mH inductor and a 2.00ohm resistor are wired in series to an ideal battery. A switch in the circuit is closed at time 0, at which time the current is 0.
(a) what is the time constant for the circuit and
(b) at what time does the current reach three-tenths its final value?