如圖所示,電源電動(dòng)勢(shì)E=10V,內(nèi)阻r=0.5Ω,“8V,16W”的燈泡恰好能正常發(fā)光,電動(dòng)機(jī)M繞組的電阻R0=1Ω,求:                                                                                                                             

(1)燈泡的電流I1;                                                                                                 

(2)電源的總電流I;                                                                                              

(3)電動(dòng)機(jī)的總功率P1;                                                                                         

(4)電動(dòng)機(jī)的熱功率P2和電動(dòng)機(jī)的機(jī)械功率P3.                                                     

                                                                                         

                                                                                                                                  


(1)燈泡的額定功率和額定電壓為8V、16W,

所以通過燈泡電流為:I1==A=2A     

(2)內(nèi)電壓U′=E﹣U=Ir   

所以總電流為 I==A=4A   

(3)電動(dòng)機(jī)總功率:P1=UI2=U(I﹣I1)=8×(4﹣2)W=16W 

(4)電動(dòng)機(jī)熱功率:P2=I2 R0=22×1=4W   

電動(dòng)機(jī)輸出功率:P3=P1﹣P2=12W.  

答:(1)燈泡的電流I1為2A;

(2)電源的總電流I為4A;

(3)電動(dòng)機(jī)的總功率P1為16W;

(4)電動(dòng)機(jī)的熱功率P2為4W,電動(dòng)機(jī)的機(jī)械功率P3為12W.


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