16. As shown in Figure A, in the long straight wire $M N$ placed next to a closed wire frame $a b c d$, the long straight wire and the wire frame in the same plane, the long straight wire through the alternating current shown in Figure B. The current along $M N$ is positive. Provide that the direction of the current along $M N$ is positive, the following statements are correct ( )
A
B
- A. A. $0 \sim t _ { 1 }$ time, an induced current along $a b c d$ direction is generated in the wire frame
- B. B. $t _ { 2 }$ moment of maximum magnetic flux through the wireframe
- C. C. $0 \sim t _ { 1 }$ time, the wireframe is subjected to an amperometric force to the right
- D. D. $t _ { 1 } \sim t _ { 3 }$ The direction of the amperometric force on the wireframe remains the same for the duration of time
Answer: C
Solution: A. In $0 \sim t _ { 1 }$ time, the current from $M$ to $N$ increases, the magnetic flux through the rectangular wire frame $a b c d$ increases inwardly, and according to Corrugated's law, $a d c b$ direction of induced current is generated in the wire frame. INLINE_FORMULA_4]] direction, so A is wrong; B. The current from $M$ to $N$ at the time of $t _ { 2 }$ is 0, and the magnetic flux through the wire frame is 0, so B is wrong;
C. $0 \sim t _ { 1 }$ time, from the analysis of the A option, through the rectangular wire frame $a b c d$ of the magnetic flux inward, the wire frame produced $a d c b$ direction of the induced current, by the left hand rule can be known, the long straight wire is subjected to the right of the amperage force, so C is correct;
D. In $t _ { 1 } \sim t _ { 2 }$ time, the current from $M$ to $N$ decreases, the magnetic flux through the rectangular wire frame $a b c d$ decreases inwardly, and according to Corrugator's law, there is a $a b c d$ in the wire frame. $a b c d$ direction of the induced current, by the left hand rule can be seen, the long straight wire by the amperage force to the left; $t _ { 2 } \sim t _ { 3 }$ time, from $N$ to $M$ the current increases, the rectangular wire frame $M$, the rectangular wire frame $M$ through the magnetic flux decreases inward, according to the flute law can be seen, the wire frame produced The magnetic flux through the rectangular wire frame $a b c d$ increases outward, and according to corrugator's law, an induced current in the $a b c d$ direction is generated in the wire frame, and by the left-hand rule, the amperage is directed to the right of the long straight wire; therefore, D is wrong.