Part 1. Nerve cells transmit electric signals through their long tubular axons. These signals propagate due to a sudden rush of Na+ ions, each with charge +e, into the axon. Measurements have revealed that typically about 5.4Af-1011 Na+ ions enter each meter of the axon during a time of 13 ms . What is the current during this inflow of charge in a meter of axon? Express your answer using two significant figures.

Part 2. A refrigerator draws 3.8 A of current while operating on a 120 V power line. If the refrigerator runs 50 % of the time and electric power costs $0.12 per kWh, how much does it cost to run this refrigerator for a 30-day month? Express your answer using two significant figures.

Part 3. Multiple Choice : A resistor R and another resistor 2.00 R are connected in parallel across a battery. If heat is produced at a rate of 16.0 W in R, in 2.00 R it is produced at a rate of

A) 64.0 W .
B) 32.0 W .
C) 16.0 W .
D) 8.00 W .