A) 7 : 25
B) 25 : 7
C) 25 : 16
D) 16 : 25
Correct Answer: B
Solution :
The ratio of magnetic moments is\[\frac{{{M}_{1}}}{{{M}_{2}}}=\frac{T_{2}^{2}+T_{1}^{2}}{T_{2}^{2}-T_{1}^{2}}\]where \[{{T}_{1}}=\]periodic time when the similar poles are on the same side \[{{T}_{2}}=\] periodic time in when the opposite poles are on the same side \[\frac{{{M}_{1}}}{{{M}_{2}}}=\frac{n_{2}^{2}+n_{1}^{2}}{n_{2}^{2}-n_{1}^{2}}\] \[(\because \,T=\frac{1}{n})\] Given \[{{n}_{1}}=15,\,\,{{n}_{2}}=20\] \[\frac{{{M}_{1}}}{{{M}_{2}}}=\frac{{{(20)}^{2}}+{{(15)}^{2}}}{{{(20)}^{2}}-{{(15)}^{2}}}=\frac{625}{175}\] \[\therefore \] \[{{M}_{1}}:{{M}_{2}}=25:7\]You need to login to perform this action.
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