(2013?Huizhou second mode) As shown in the figure, is Xiaoming research "affect the magnetic strength of the electromagnet factors" device diagram, it is by the power supply, sliding varistor, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch, switch.
(1) When the switch is closed, the right end of the electromagnet should be S pole.
(2) when the slider P slide to the left, the sliding varistor resistance increases, the current in the coil decreases, the electromagnet magnetism "weakened".
The answer is: (1) S.
(2) left; weakened.
The answer is: (1) S.