Answer:
The magnitude of the force, B = 5 Tesla, Up (North) direction
Explanation:
Magnetic force F= Eq where Electric field, E = 750 NC
and charge, q = -70 μC = -7 ×C
F = 750 × -7 ×
F = 0.0525
But F = qvB; B =
where B is the magnetic field
= 0.0525 ÷ ( -7 × × 30)
B = 5.0 Teslas
The force on a negative charge is in exactly the opposite direction to that on a positive charge.
Hence the direction of the charge is up (North).