A. \({\rm{\Delta }}\phi {\mkern 1mu} = {\mkern 1mu} {2,5.10^{ - 3}}{\mkern 1mu} {\rm{W}}b.\)
B. \({\rm{\Delta }}\phi {\mkern 1mu} = {\mkern 1mu} {25.10^{ - 3}}{\mkern 1mu} {\rm{W}}b.\)
C. \({\rm{\Delta }}\phi {\mkern 1mu} = {\mkern 1mu} {2,5.10^{ - 4}}{\mkern 1mu} {\rm{W}}b.\)
D. \({\rm{\Delta }}\phi {\mkern 1mu} = {\mkern 1mu} 0,25{\mkern 1mu} {\rm{W}}b.\)
B
\(\begin{array}{l} {\rm{\Delta }}\phi = {\phi _1}{\mkern 1mu} - {\mkern 1mu} {\phi _2} = NS.cos\alpha ({B_2} - {B_1})\\ {\mkern 1mu} = {1000.25.10^{ - 4}}{.10^{ - 2}} = {25.10^{ - 3}}{\rm{W}}b. \end{array}\)
Câu hỏi trên thuộc đề trắc nghiệm dưới đây !
Copyright © 2021 HOCTAP247