At t = 0, an inductor of zero resistance is joined to a cell of emf

1.	At t = 0, an inductor of zero resistance is joined to a cell of emf ℰ through a resistance. The current increases with a time constant τ. The emf across the coil after time t is(a) ℰ t/τ.(b) ℰ (1 - e -t/τ)(c) ℰ e -t/τ(d) ℰ e 2-t/τ
Answer» Correct Answer is: (c) ℰ e ^-t/τ i = i₀(1 - e ^-t/τ) di/dt = -i₀ (-1/τ) e ^-t/τ = ℰ /R. R/L. e^-t/τ or L di/dt = ℰ e ^{-t/τ =} emf across the coil.

At t = 0, an inductor of zero resistance is joined to a cell of emf ℰ through a resistance. The current increases with a time constant τ. The emf across the coil after time t is(a) ℰ t/τ.(b) ℰ (1 - e -t/τ)(c) ℰ e -t/τ(d) ℰ e 2-t/τ

Answer»

Correct Answer is: (c) ℰ e ^-t/τ

i = i₀(1 - e ^-t/τ)

di/dt = -i₀ (-1/τ) e ^-t/τ = ℰ /R. R/L. e^-t/τ

or L di/dt = ℰ e ^{-t/τ =} emf across the coil.

Discussion

No Comment Found

Related InterviewSolutions

Statement I : The resistance of a copper wire varies directly as the length and diameter. Statement II : Because the resistance varies inversely the area of cross-section.A. If both Statement- I and Statement- II are true, and Statement - II is the correct explanation of Statement– I.B. If both Statement - I and Statement - II are true but Statement - II is not the correct explanation of Statement – I.C. If Statement - I is true but Statement - II is false.D. If Statement - I is false but Statement - II is true.
Statement I : Force between two charges decreases when air separating the charges is replaced by water. Statement II : Medium intervening the charges has no effect on force.A. If both Statement- I and Statement- II are true, and Statement - II is the correct explanation of Statement– I.B. If both Statement - I and Statement - II are true but Statement - II is not the correct explanation of Statement – I.C. If Statement - I is true but Statement - II is false.D. If Statement - I is false but Statement - II is true.
Assertion. Capacity of a parallel plate condenser remains unaffected on introduced a conducting or insulating slab between the plates. Reason. In both the cases, electric field intensity between the plates increases.A. If both Statement- I and Statement- II are true, and Statement - II is the correct explanation of Statement– I.B. If both Statement - I and Statement - II are true but Statement - II is not the correct explanation of Statement – I.C. If Statement - I is true but Statement - II is false.D. If Statement - I is false but Statement - II is true.
Two circular, similar, coaxial loops carry equal currents in the same direction. If the loops are brought nearer, what will happen?A. Current will increase in each loop.B. Current will decrease in each loop.C. Current will remain same in each loop.D. Current will increase in one and decrease in the other.
Define the term Armature?
What is Short circuiting?
The potential difference between points A and B is - A. `2 V`B. `6 V`C. `4 V`D. `3 V`
If a copper wire is stretched to make its radius decrease by `0.1%`, then the percentage increase in resistance is approximately -A. `0.1 %`B. `0.2%`C. `0.4%`D. `0.8%`
Write the differences between AC generator and DC motor.
What is the difference between AC and DC generator?

At t = 0, an inductor of zero resistance is joined to a cell of emf ℰ through a resistance. The current increases with a time constant τ. The emf across the coil after time t is(a) ℰ t/τ.(b) ℰ (1 - e -t/τ)(c) ℰ e -t/τ(d) ℰ e 2-t/τ

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment