Bài 2:
`a=10cm` `\to` `S=10.10=100(cm^2)=100.10^-4(m^2)`
`alpha=90^o-90^o=0^o`
`Δt=0,05s`
`ΔB=B_2-B_1=2-0,5=1,5(T)`
a.
`ΔФ=ΔB.S.cos\alpha=1,5.100.10^-4.cos0^o=0,015` `(Wb)`
b.
`e_{cư}=\frac{|ΔФ|}{Δt}=(0,015)/(0,05)=0,3(V)`
c.
`I_{cư}=e_{cư}/R=(0,3)/(0,01)=30(A)`
Bài 3:
`l=62,8(cm)=62,8.10^-2(m)`
`N=1000` vòng
`S=50(cm^2)=50.10^-4(m^2)`
`I=4A`
a.
`L=4.pi.10^-7.(N^2.S)/l=4.pi.10^-7.(1000^2. 50.10^-4)/(62,8.10^-2)=0,01(H)`
b.
`e_{tc}=-L.(Δi)/(Δt)=-0,01.\frac{0-4}{0,01}=4(V)`
