JEE PYQ: Alternating Current Question 34
Question 34 - 2019 (10 Apr Shift 2)
A coil of self inductance 10 mH and resistance 0.1 $\Omega$ is connected through a switch to a battery of internal resistance 0.9 $\Omega$. After the switch is closed, the time taken for the current to attain 80% of the saturation value is [take $\ln 5 = 1.6$]:
(a) 0.324 s (b) 0.103 s (c) 0.002 s (d) 0.016 s
Show Answer
Answer: (d)
Solution
$R = 1\Omega$. $e^{-100t} = 0.2$. $t = \frac{\ln 5}{100} = 0.016$ s.
BETA
