Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Open MARKS Web Download App
Search any question & find its solution
Question: Answered & Verified by Expert
In the given figure the work done by the battery after the switch S is closed is

PhysicsElectrostaticsJEE Main
Options:
  • A 1 0 0  μ J
  • B - 1 0 0  μ J
  • C 8 0  μ J
  • D - 8 0  μ J
Solution:
2515 Upvotes Verified Answer
The correct answer is: 8 0  μ J
Before the switch S is closed

Q i = C eq V

     = 5 × 4 = 2 0  μ C

When the switch S is closed

Q f = CV

    = 1 0 × 4 = 4 0  μ C

W cell = Δ QE = Q f - Q i × E

            = 2 0 × 4 = 8 0  μ J

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.

Use on iOS or Desktop Download from Google Play