1 hm=100m
1.5hm=150 meters each tower is from each other.
500km(1000m/1km)=500,000 meters the wire covers.
500,000/150 = 3333.33 towers. Just because we want to be safe and have enough towers we can say we have 3334 towers in the span of 500,000 meters.
B)
1kV=1000V
500kV(1000V/1kV)= 500,000 V
There are 1.2 volts in a AA battery so we divide 500,000/1.2 = 416666.67 times larger