(2) As can be seen from the figure, when the magnetic field is enhanced, the resistance value of magnetoresistance increases; When there is no magnetic field, the resistance of magnetoresistance is not zero, so the image is the origin.
(3)① Let the sliding rheostat control the current, that is, connect as shown in the figure.
② R=UI: r = 1.5v0.003a = 500ω。
③ As can be seen from the figure, when the resistance is 500 Ω, the intensity of magnetic induction line is1.0t.
(4) When the resistance moves from 1 to 2, the strength of the magnetic induction line becomes smaller and the magnetic resistance becomes smaller, so the current in the circuit increases. If the other resistors except the magnetoresistance remain unchanged, the voltage on the other resistors increases and the power supply voltage remains unchanged, then the voltage applied to the magnetoresistance decreases, increases and decreases.
(4) Some properties of the magnetic field can be considered: For example, is the resistance of magnetoresistance related to the direction of the magnetic field? (or is the magnetic field distribution spatially symmetric? Or will the magnetic field change after the magnetic pole is hit? )
(5) As can be seen from the figure, when the magnetic field is removed, the magnetic resistance is
r = 100ω
According to ohm's law, the total resistance in a circuit
R total = ui =UI=550？ Ω
The resistance of sliding rheostat is calculated as follows
R slip =R total-r = 550ω-100ω = 450ω;
So the answer is: (1)N (north), a.
(2) Before the magnetic field is increased and put into operation, the magnetic resistance is not 0;
(3)① Connect as shown above; ②500; ③ 1.0; ④ Increase or decrease;
(4) Is the resistance of magnetoresistance related to the direction of magnetic field? (or is the magnetic field distribution spatially symmetric? Or will the magnetic field change after the magnetic pole is hit? )
(5) The resistance of sliding rheostat is 450Ω.