The time taken for the magnetic energy to reach 25 % of its maximum value, when a solenoid of resistance R ,…

The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is :
  1. LRln5
  2. infinite
  3. LRln2
  4. LRln10

Solution

Magnetic energy =12Li2=25%

ME⇒25%⇒i=i02

i=i01-R-Rt/L for charging

t=LRln2

Asked in: JEE Main 2021 (18 Mar Shift 2)

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