Answer:
2) deflection must be towards the negative side of the voltage.
4) the correct statements are: b and c
Explanation:
2) This question is based on Faraday's law of induction, when we introduce a magnet in a solenoid an induced current is produced that generates a voltage that is given by
E = - N d / dt
where = B. A
The bold are vectors
Therefore, when applying this formula to our case, the induction lines of the magnetic field increase as we approach the solenoid, as the South pole approaches the lines are in the direction of the magnet, therefore the normal to the solenoid that has an outgoing direction and the magnetic field has 180º between them and the cos 180 = -1; consequently the deflection must be towards the negative side of the voltage.
4) From the Faraday equation we can see that the inductive electromotive force depends
* The magnitude of B that changes over time
* The area of the loop that changes over time
* The angle between B and the area that changes over time
* A combination of the above
With this analysis we will review the different alternatives given
a) False. It takes a temporary change and an absolute value of B
b) True. As the speed decreases, the change in B decreases, that is, dB / dt decreases
c) True. The current is induced in each turn, if there is a smaller number the total current will be smaller
d) False. A temporary change of area is needed, in addition to increasing the area the current increases
We can see that the correct statements are: b and c