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JEE Main 20207 JanuaryEvening Shift
Exam
JEE Main
Year
2020
Date
7 January
Shift
Evening Shift
Subject
Physics
Chapter
Capacitance

JEE Main 2020 · 7 January · Evening Shift · Physics · Capacitance

A 60pF capacitor is fully charged by a 20V supply. It is then...

A 60pF60pF capacitor is fully charged by a 20V20V supply. It is then disconnected from the supply and is connected to another uncharged 60pF60pF capacitor in parallel. The electrostatic energy that is lost in this process by the time the charge is redistributed between them is (in nJnJ ) ________A 60pF capacitor is fully charged by a 20V supply. It is then disconnected from the supply and is connected to another

Correct answer

0

Step-by-step solution

A 60pF capacitor is fully charged by a 20V supply. It is then disconnected from the supply and is connected to another
V0=20V{V}_{0} = 20V
Heat loss =Ui−Ut= {U}_{i} - {U}_{t}
=12Cvo2−2[12C(V02)2]= \dfrac{1}{2}C{v}_{o}^{2} - 2\left[\dfrac{1}{2}C{\left(\dfrac{{V}_{0}}{2}\right)}^{2}\right]
=CVo24= \dfrac{C{V}_{o}^{2}}{4}
=(60×10−12)(20)24J= \dfrac{\left(60 \times {10}^{- 12}\right){\left(20\right)}^{2}}{4}J
=6×10−9J=6nJ= 6 \times {10}^{- 9}J = 6nJ
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