Question 101: Electromagnetic Induction

Question

A 20 Henry inductor coil is connected to a
10 ohm resistance in series as shown in figure.
The time at which rate of dissipation of energy
(joule's heat) across resistance is equal to the
rate at which magnetic energy is stored in the
inductor is :

Accepted Answer

P
R
= i
2
ÃÂ R
P
B
= V ÃÂ i
$$ 	herefore $$ P
L
= Vi Ã¢ÂÂ i
2
R
$$ \Rightarrow $$ Vi Ã¢ÂÂ i
2
R = i
2
R
$$ \Rightarrow $$ $$i = {V \over {2R}}\,\,and\,\,i = {V \over R}\left( {1 - {e^{ - t/	au }}} ight)$$
$$ 	herefore $$ $${V \over {2R}} = {V \over R}\left( {1 - {e^{ - t/	au }}} ight)$$
$$ \Rightarrow $$ t = $$	au $$ln(2) = $${{20} \over {10}}ln(2) = 2ln(2)$$

Answer

$${2 \over {\ln 2}}$$

Answer

$${\ln 2}$$

Answer

$$2{\ln 2}$$

Answer

$${1 \over 2}{\ln 2}$$

Electromagnetic Induction

A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (joule's heat) across resistance is equal to the rate at which magnetic energy is stored in the inductor is :

Choose the correct answer: