Question bank/JEE Main/Physics

JEE MainPhysicsModerateCurrent Electricity

In the figure shown C1=11μFC_{1} = 11\mu F and C2=5μFC_{2} = 5\mu F then
at steady state

Show answer and solution
[IMAGE] at steady state
I(3)+1(2)=15I(3) + 1(2) = 15
I = 3

kvLkvL
C→D→E→a→b→CC \rightarrow D \rightarrow E \rightarrow a \rightarrow b \rightarrow C
Vc−I(3)+q11−7+q5=VcV_{c} - I(3) + \frac{q}{11} - 7 + \frac{q}{5} = V_{c}
q11+q5=7+3×3=16\frac{q}{11} + \frac{q}{5} = 7 + 3 \times 3 = 16
q=55μCq = 55\mu C
Now KVL for a
→\rightarrowb
Va−7+q5=VbV_{a} - 7 + \frac{q}{5} = V_{b}
⇒Va−Vb=7−q5\Rightarrow V_{a} - V_{b} = 7 - \frac{q}{5}
=7−555= 7 - \frac{55}{5} =−205=−4V= - \frac{20}{5} = - 4V

Source: Grass-G / Ph-28 Physics paper FST 16 Jan.docx

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