Question

Magnetic field exists in a region of space if a moving charge there experiences a force due to its motion.

A. True

B. False

Answer 1

According to the Biot-Savart law, a moving charge produces a magnetic field around itself (see https://cnx.org/contents/atl-mE0g@1/The-Biot-Savart-Law-for-point-charges-and-wires). If the net force on the charge is not zero (which is the case in this problem), it must move and, this, magnetic field must exist.

Answer. True.