如圖所示,電壓的瞬時(shí)表達(dá)式為()。
A.u=10√2sin(50πt–π/4)V B.u=10√2sin(50πt+π/4)V C.u=10√2sin(100πt-π/4)V D.u=10√2sin(100πt+3π/4)V
A.三個(gè)燈都將變暗 B.燈將因過亮而燒毀 C.仍能正常發(fā)光 D.立即熄滅
A.6Var B.8Var C.10Var D.14Var