Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
Two identical capacitors A and B, charged to the same potential 5V are connected in two different circuits as shown below at time t=0. If the charge on capacitors A and B at time t=CR is QA and QB respectively, then (Here e is the base of natural logarithm)

PhysicsAlternating CurrentJEE MainJEE Main 2020 (09 Jan Shift 2)
Options:
  • A QA=VCe,QB=CV2
  • B QA=VC,QB=CV
  • C QA=VC,QB=VCe
  • D QA=CV2,QB=VCe
Solution:
2954 Upvotes Verified Answer
The correct answer is: QA=VC,QB=VCe

Charge on capacitor after charging with a battery of potential VQ=CV

Now, capacitor A is connected as shown in the figure.

As diode is in reverse bias, so capacitor charge remains same after time t=CR.

 QA=CV

In case B, capacitor is connected as shown in the figure.

Here, diode is in forward bias, so capacitor discharges and its charge decays as 

QB=Q·e-tRC

where, t=RC

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.