[单选题]
The diagram below shows a circuit connected to an iron rod
b c +e09lxcynzz-j8(;l;v bh le/kc8jXY. The connecting
te m4mks;hxqhiv9d7 4;mr4h l6lm, w- wires are flexible. The rod is placed in a magnetic field directed perpendicularly into th
e,4;mviqhh xrdlm ks6t;m4w-97mh l4 e 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.
