Answer:

Explanation:
Let the linear charge density of the charged wire is given as

here we can use Gauss law to find the electric field at a distance r from wire
so here we will assume a Gaussian surface of cylinder shape around the wire
so we have

here we have


so we have

Distance = speed X time
In this example, the speed of the airplane = 840km. The time (that the question is asking)is how far can it travel in 1 hour.
So just plug in your numbers.
Distance = 840km X 1 hour = 840km/hour or 840km for short.
I’m pretty sure it’s lean mass but let another guy answer you before you use mine
The correct option is D.
A step up voltage transformer is a type of transformer which increases voltage from primary to secondary turns. The transformer has more secondary winding turns than primary winding turns. A step up transformer is designed to increase voltage because high voltage increases efficiency.<span />
THE ANSWER IS B HOPE I COULD HELP