giai bai chum tian sang mat troi xem la chum sang song song chieu xieng den mat dat mot hoc sinh khang dinh co the do duoc chieu cao cua cot dien hoc sinh ay dung cau coc cam thang dung tren mat daat phan coc nho len cao 1m do bong cai coc tren mat daat dai 0.4m bong, cot dien tren mat dat dai 2,2m tu ddo tinh duoc chieu cao cot dien ban ay da tinh nhu the nao va cot dien cao bao nhieu

Cho 4 bong den 1 khoa k 1 nguon     dien va cac day dan . Cau a ) khoa k mo , 3 dèn dáng va 1 den tat . Cau b ) khoa k dong ,4 den sang . Ve so do mach dien       

hay ve so do mot mach dien gom 1 pin,mot khoaK,2den mac noi tiep va ve mui ten chi chieu dong dien trong mach theo qui uoc

cho 3 bong den. Hoi co the lap duoc tat ca bao nhieu mach dien khac nhau. ve tat ca cac mach dien ay.

Mau len nhe mn. Thu hai tuan sau mk thi roi

ve mach dien gom nguon 3 pin mac noi tiep hai bong den va 1 cong tac o cac tuong hop sau

a ca 2 den sang cong tac dong

b 1 den tat va 1 den sang cong tac mo

c cong tac mo 2 den deu sang va cong tac dong thi 1 den tat 1 den sang?

Cho mach dien gom 2 pin mac noi tiep,D1,D2,D3,khoa K1,K2 va day noi

Ve so do mach dien thoa man cac yeu cau sau

a)K1 dong,K2 mo thi D1 tat,D2,D3 sang

b)K1 mo,K2 dong thi chi co D1 sang

c)Ca 2 cung dong thi ca 3 den cung tat

Mach dien gom 2 bong den mac noi tiep,1 cong tac k, nguon dien 2 pin , mot so day dan a) ve so do mach dien trong do co cuc duong noi voi khoa k.chi chieu dong dien chay trong mach b) neu 3 nguyen nhan ( co the) neu dong khoa den khong sang c) nguoi ta mac them mot mach vao cau chi de bao ve mach dien . Neu nguyen tac hoat dong tac dung cua cau chi trong mach dien

Cho mach dien gom 2 pin mac noi tiep,D1,D2,D3,khoa K1,K2 va day noi

Ve so do mach dien thoa man cac yeu cau sau

a)K1 dong,K2 mo thi D1 tat,D2,D3 sang

b)K1 mo,K2 dong thi chi co D1 sang

c)Ca 2 cung dong thi ca 3 den cung sang