Consider an electrical circuit containing a two way switch '$S$'. Initially $S$ is open and then $T_{1}$ is connected to $T_{2}$. As the current in $\mathrm{R}=6\Omega$ attains a maximum value of steady state level, $\mathrm{T}_{1}$ is disconnected from $\mathrm{T}_{2}$ and immediately connected to $\mathrm{T}_{3}$. Potential drop across $\mathrm{r}=3\Omega$ resistor immediately after $T_{1}$ is connected to $T_{3}$ is ______ V. (Round off to the Nearest Integer)

JEE Main · 2021 · 27 Jul 2021 · Shift 1 · Electromagnetic Induction

Consider an electrical circuit containing a two way switch '

S

'. Initially

S

is open and then

T_{1}

is connected to

T_{2}

. As the current in

R = 6Ω

attains a maximum value of steady state level,

T_{1}

is disconnected from

T_{2}

and immediately connected to

T_{3}

. Potential drop across

r = 3Ω

resistor immediately after

T_{1}

is connected to

T_{3}

is ______ V. (Round off to the Nearest Integer)

Answer: 3

With

T_{1}

joined to

T_{2}

the battery drives current through

R

and the inductor. In the steady state the inductor offers no opposition, so the current settles at

I = \frac{6}{6} = 1 A

Current through an inductor cannot change abruptly, so at the instant

T_{1}

is thrown to

T_{3}

this same

1

A continues, now driven round the loop containing

r

. The drop across that resistor is

V = I r = 1 \times 3

. Immediately after switching, the potential drop across the

3 Ω

resistor is

3

JEE Main · 2021 · 27 Jul 2021 · Shift 1 · Integer answer