An electric charge +q moves with velocity →v=3^i+4^j+^k in the presence of electric and magnetic fields given by →E=3^i+^j+2^k and →B=^i+^j−3^k. The y-component of the force experienced by +q is ?
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Solution
Using Lorentz's force equation,
→F=q(→E+(→v×→B))
Given,
→E=3^i+^j+2^k→V=3^i+4^j+^k→B=^i+^j−3^k
Putting values in →F we get,
→F=q[3^i+^j+2^k+(3^i+4^j+^k)×(^i+^j−3^k)]
=q[3^i+^j+2^k+3^k+9^j−4^k−12^i+^j−^i]
→F=q[−10^i+11^j+^k]
|→Fy|=11q
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Hence, option (b) is the correct answer.
Why this question ?
To familiarize oneself how to use Lorentz force equation in different scenarios and to make vector calcualtion familiar.