Answer:
The speed of the electron is
.
Explanation:
Given that,
The magnitude of electric field, 
The magnitude of magnetic field, B = 0.516 T
Both the magnetic and electric fields are acting on the moving electron. Then, the magnitude of electric field and magnetic field is balanced such that :

or

So, the speed of the electron is
. Hence, this is the required solution.
Ocean currents are formed by a type of heat transfer that is convection
We have the equation of motion
, where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.
Here displacement = 135 m, Initial velocity = 0 m/s, acceleration = 9.81
Substituting

A box falls out of a stationary helicopter hovering 135 m above the ground will take 5.25 seconds to reach the ground.