An implanted pacemaker supplies the heart with 72 pulses per minute, each pulse providing 6.0 v for 0.65 ms. the resistance of the heart muscle between the pacemaker’s electrodes is 550ω. find (a) the current that flows during a pulse, (b) the energy delivered in one pulse, and (c) the average power supplied by the pacemaker.

a) 0.11 Amp b) 0.000429 Joules c) 0.000514 watt

Explanation:

a)current

I=V/r I=6.0/550 =1.1*10^-2 A

b) energy

E= 1.1*10^-2 x (6.0) x 0.00065s(<-- remember to convert ms to seconds) = 0.000429J

C) Average power

P = (0.000429 x 72) / 60

P = 0.000514 W

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?