A) 4 : 3
B) 25 : 7
C) 7 : 5
D) 25 : 16
Correct Answer: B
Solution :
Ratio of magnetic moments of two magnets of equal size when in sum and difference position is \[\frac{{{M}_{A}}}{{{M}_{B}}}=\frac{T_{d}^{2}+T_{s}^{2}}{T_{d}^{2}-T_{s}^{2}}=\frac{v_{s}^{2}+v_{d}^{2}}{v_{s}^{2}-v_{d}^{2}}\] \[\frac{={{\left( \frac{1}{20} \right)}^{2}}+{{\left( \frac{1}{15} \right)}^{2}}}{{{\left( \frac{1}{15} \right)}^{2}}-{{\left( \frac{1}{20} \right)}^{2}}}\] \[=\frac{400+225}{400-225}\] \[=\frac{625}{175}=\frac{25}{7}\] \[\Rightarrow \] \[{{M}_{A}}:{{M}_{B}}=25:7\]You need to login to perform this action.
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