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MODEL PAPER 5 — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsMODEL PAPER 53 Marks
Question
$a.$ Write the relationship between mobility and drift velocity in a current carrying conductor.
$b.$ Two aluminium wires have their lengths in the ratio $2 : 3$ and radii in the ratio $1 : 3.$ These are connected in parallel across a battery of emf $E$ and of negligible internal resistance. Find the ratio of drift velocities of the electrons in the two wires.
✓

Answer

$a. \mu=\frac{V_d}{E}$
$b.V _{ d }=\frac{e \tau E}{m}=\frac{e \tau V}{m l}$
$\frac{V_{d l }}{V_{d 2}}=\frac{l_2}{l_1}=\frac{3}{2}$
Hence, the ratio of drift velocities of the electrons in the two wires is $3:2$

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