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Two point charges of +1muC and +4muC are kept 30 cm apart. How far from the +1muC charge on the line joining the two charges, will the net electric field be zero? |
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Answer» Solution :Let charges of `q_(1)=1muC and q_(2)=+4muC` be kept fixed at point A and B RESPECTIVELY situated at a distance 30 cm apart. Let net electric field be zero at a point O situated at a distance x cm from CHARGE A as shown in figure. Then, at point O `vecE_(A)+vecE_(B)=vec0 or |vecE_(A)|= |vecE_(B)| and vecE_(A) and vecE_(B)` MUST be in MUTUALLY opposite DIRECTIONS  `rArr (1)/(4pi in_(0)). (q_(1))/(x^(2))=(1)/(4pi in_(0)). (q_(2))/((30-x)^(2))` `rArr (1muC)/(x^(2))=(4muC)/((30-x)^(2))rArr x=10cm or 0.1m` |
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