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An ionized gas contains both positive and negative ions . If it is subjected simultaneously to an electric field along the ` +x` - direction and a magnetic field along the ` +y` - direction and the negative ions towardws `-y` - directionA. positive ions deflect towards ` +y-direction` and negative ions towards `- y direction`B. all ions deflect towards ` +y -direction`C. all ions deflect towards ` - y -direction`D. positive ions deflect towards ` - y-direction` and negative ions towards `+ y direction` |
Answer» Correct Answer - C Case of positively charged particle : Two forces are acting on the positively charged particle (a) due to electric field in the positive ` x- direction` (b) Force due to magnetic field. ` vec(F) = q (v hat(i)xxB hat(k)) rArr vec(F) = qvB hat(-j)` this forces will move the positively charged particle towards ` Y - axis `. Case of negatively charged particle. Two forces are acting on the negatively charged particle (a) due to eletric field in the negative ` x- direction` . (b) due to magnetic field ` vec(F) = -q(vec(v)xxvec(B))` vec(F) = -q[ v( hat (-i) xxB hat (k))]` ` vec (F) = -qvB[ hat(i) xx hat(k)] , vec(F) = qvB hat(-j)` Same direction as that of positive charge . (c) is the correct answer. |
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