MCQ
When the current $i$ is flowing through a conductor, the drift velocity is $v$. If $2i$ current is flowed through the same metal but having double the area of cross-section, then the drift velocity will be
- A$v/4$
- B$v/2$
- ✓$v$
- D$4\,v$
✓
Answer
Correct option: C.
$v$
c
${v_d} = \frac{J}{{ne}}$ $\Rightarrow $ ${v_d} \propto \,J$ (current density)
${v_d} = \frac{J}{{ne}}$ $\Rightarrow $ ${v_d} \propto \,J$ (current density)
${J_1} = \frac{i}{A}$ and ${J_2} = \frac{{2i}}{{2A}} = \frac{i}{A} = {J_1}$; ${({v_d})_1} = {({v_d})_2} = v$
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