[单选题]
The diagram below sho
o 0ju zl 7:5k29buruc-subn 1mvg4hwa9v;ry9 ws a circuit connected to an iron rod XY. The c
/mzr 9pvdo(k0khag64 onnecting wires are flexible
p0 kgv(/ 4ok6r 9adzmh. The rod is placed in a magnetic field directed perpendicularly into the page as shown.
In what direction will the resultant force act on the rod when the current is switched on in the circuit?
A. Upwards
B. Downwards
C. Away from the observer
D. Towards the observer
参考答案:
B
本题详细解析:
Explanation:
Conventional current will flow anticlockwise due to the orientation of the cell. To determine the force experienced by a current carrying conductor in a magnetic field, use (any appropriate hand-rule convention or) Flemming's left hand rule which states that if we arrange our thumb, forefinger and middle finger of the left-hand perpendicular to each other, then the thumb points towards the direction of the force experienced by the conductor, the forefinger points towards the direction of the magnetic field and the middle finger points towards the direction of the electric current.