(2010)圖示電路中,電流源的端電壓U等于:()
A.20V B.10V C.5V D.0V
A.0.05V B.0.15V C.0.2V D.0
如圖所示,導(dǎo)體回路處在一均勻磁場(chǎng)中,B=0.5T,R=2Ω,ab邊長(zhǎng)L=0.5m,可以滑動(dòng),a=60°,現(xiàn)以速度υ=4m/s將ab邊向右勻速平行移動(dòng),通過(guò)R的感應(yīng)電流為:()
A.0.5A B.-1A C.-0.86A D.0.43A