In which case the torque exerted by uniform steady magnetic field on a closed circuit electric current is zero? The torque exerted by magnetic field on closed circuit electric current is never zero. When the magnetic field is parallel to circuit's surface (perpendicular to the circuit's vector area). When the magnetic field makes an angle of 45 with the circuit's vector area. When the magnetic field is perpendicular to circuit's surface (parallel to the circuit's vector area).