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2. Electric potential and capacitance — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics2. Electric potential and capacitance1 Mark
MCQ
A variable condenser is permanently connected to a $100$ $V$ battery. If the capacity is changed from $2\,\mu \,F$ to $10\,\mu \,F$, then change in energy is equal to
  • A
    $2 \times {10^{ - 2}}\,J$
  • B
    $2.5 \times {10^{ - 2}}\,J$
  • C
    $3.5 \times {10^{ - 2}}\,J$
  • ✓
    $4 \times {10^{ - 2}}\,J$
✓

Answer

Correct option: D.
$4 \times {10^{ - 2}}\,J$
d
(d) $\Delta U = {U_2} - {U_1} = \frac{{{V^2}}}{2}({C_2} - {C_1})$
$ = \frac{{{{(100)}^2}}}{2}(10 - 2) \times {10^{ - 6}} = 4 \times {10^{ - 2}}\,J$

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