JEE Main · 2022 · 27 Jun 2022 · Shift 1 · Capacitance

WhatsApp Email

A capacitor of capacitance 50 pF is charged by 100 V source. It is then connected to another uncharged identical capacitor. Electrostatic energy loss in the process is ______ nJ.

Answer: 125

Solution

When two capacitors are connected, charge redistributes until both reach the same potential. The energy loss in this process is:

Δ U = \frac{1}{2} \frac{C _{1} C _{2}}{C _{1} + C _{2}} (V_{1} - V_{2})^{2}

For identical capacitors (

C_{1} = C_{2} = 50

pF) with initial voltages

V_{1} = 100

V and

V_{2} = 0

Δ U = \frac{1}{2} \frac{50 \times 50}{50 + 50} \times 1 0^{- 24} \times (100)^{2} = \frac{1}{2} \times 25 \times 1 0^{- 12} \times 1 0^{4} = 125 \times 1 0^{- 9} J = 125 nJ

JEE Main · 2022 · 27 Jun 2022 · Shift 1 · Integer answer

Practise more: all JEE Main PYQs on Capacitance →

More JEE Main questions on Capacitance

A capacitor $P$ with capacitance $10 \times 1 0^{- 6} F$ is fully charged with a potential difference of 6.0 V and disconnected from the battery. The charged capacitor $P$ is connected across another capacitor $Q$ with capacitance $20 \times 1 0^{- 6} F$ . The char …
JEE Main 2026View solution →
The space between the plates of a parallel-plate capacitor of capacitance C (without any dielectric) is now filled with three dielectric slabs of dielectric constants $K_{1} = 2, K_{2} = 3$ , and $K_{3} = 5$ (as shown in the figure). If new capacitance is …
JEE Main 2026View solution →
A parallel plate capacitor with plate separation 5 mm is charged by a battery. On introducing a mica sheet of 2 mm and maintaining the connections of the plates with the terminals of the battery, it is found that it draws $25%$ more charge from the battery. The dielectric con …
JEE Main 2026View solution →
Three parallel plate capacitors each with area A and separation d are filled with two dielectric (k₁ and k₂) in the following fashion. Which of the following is true? (k₁ > k₂)
JEE Main 2026View solution →
Identify the correct statements :
A. Effective capacitance of a series combination of capacitors is always smaller than the smallest capacitance of the capacitor in the combination.
B. When a dielectric medium is placed between the charged plates of a capacitor, displacement of c …
JEE Main 2026View solution →
A parallel plate capacitor has capacitance C , when there is vacuum within the parallel plates.
A sheet having thickness $(\frac{1}{3})^{rd}$ of the separation between the plates and relative permittivity K is introduced between the plates. The new capacitan …
JEE Main 2026View solution →