Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

Fig. 211

260 Aptitude Test Problems in Physics

3.23. After adding two conductors, the circuit will
acquire the form shown in Fig. 211. From symmetry
considerations, we conclude that the central con-

A

Fig. 210

ductor will not participate in electric charge
transfer. Therefore, if the initial resistance R 1
of the circuit was 5r, where r is the resistance of

a conductor, the new resistance of the circuit will

become

r

R 2 2r +

2

= 3r.

2

Therefore,

R2 3

RI

—5.

3.24. The total resistance RA B of the frame can

easily be calculated by noting from symmetry

considerations that there is no current in the edge