When the A board and the A board move upward, the capacitance decreases. Q remains the same, then u will increase. The opening angle of the electrometer pointer becomes larger. pair

B and B plates move to the right. When D increases, the capacitance decreases. Q remains the same, then u will increase. The opening angle of the electrometer pointer becomes larger. B ok.

C and ε increase, and capacitance increases. Q remains the same, u will decrease. The opening angle of the electrometer pointer becomes smaller. C cuo

When d and c remain the same, q decreases and u decreases. The opening angle of the electrometer pointer becomes smaller. wrong

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