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Consider the situation shown in . The wire PQ has a negligible resistance and is made to slide on the three rails with a constant speed of `5 cm s^(-1)` . Find the current in the `10 Omega` resistor when the switch S is thrown to (a) the middle rail (b) the bottom rail. A. zeroB. 2 mAC. 3 mAD. None of these |
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Answer» Correct Answer - D Here `B=1T, v=5 xx 10^(-2) m//s, R=1 Omega` When the switch is thrown to the middle rail `E=Bvl` `=1 xx 5 xx 10^(-2) V` `=10 xx 10^(-4) =10^(-3)V` Current in the `10 Omega` resistor =`E//R` `(10^(-3))/(10) =10^(-4) = 0.1 mA` The switch is thrown to the lower rail `E=Bvl` `=1 xx 5 xx 10^(-2) xx 4 xx 10^(2) = 20 xx 10^(-4)V` Current `=(20 xx 10^(-4))/(10) = 2 xx 10^(-4) = 0.2 mA`. |
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