Question 1

In a series LRC circuit an inductor will be dominant at higher frequencies.

Accepted Answer

True

Question 2

If the current increases in a solenoid, the induced emf acts to
A)decrease the flux.
B)increase the flux.
C)first increase then decrease the flux.
D)first decrease then increase the flux.
E)have no effect on the flux.

Accepted Answer

According to Lenz's Law, the induced emf in a solenoid will act in a direction to oppose the change in current, thereby decreasing the magnetic flux through the solenoid.

Question 3

A series LRC circuit connected across an ac voltage source has minimum current flowing through the circuit when operating at the resonant frequency.

Accepted Answer

In a series LRC circuit, the current is maximum at the resonant frequency because the inductive and capacitive reactances cancel each other out, resulting in only the resistive component affecting the current.

Question 4

A resistor and an inductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the inductor is
A)greater than the battery's terminal voltage.
B)equal to the battery's terminal voltage.
C)less than the battery's terminal voltage, but not zero.
D)zero.

Accepted Answer

At the moment contact is made, the inductor initially opposes any change in current, so the entire battery voltage appears across the inductor.

Question 5

Starting from zero, an electric current is established in a circuit made of a battery of emf E, a resistor of resistance R and an inductor of inductance L. The electric current eventually reaches its steady-state value. What would be the effect of using an inductor with a larger inductance in this circuit?
A)The steady-state value of the current would be larger, but it would take the same amount of time to reach it.
B)The steady-state value of the current would be the same, but it would take more time to reach it.
C)The steady-state value of the current would be the same, but it would take the same amount of time to reach it.
D)The steady-state value of the current would be larger, but it would take more time to reach it.
E)The steady-state value of the current would be the same, but it would take less time to reach it.

Accepted Answer

The steady-state current is determined by Ohm's Law (I = E/R) and is independent of the inductance. However, a larger inductance increases the time constant (L/R), causing the current to take more time to reach its steady-state value.

Question 6

A resistor and an inductor are connected in series to a battery. The time constant for the circuit represents the time required for the current to reach
A)25% of the maximum current.
B)37% of the maximum current.
C)50% of the original value.
D)63% of the maximum current.
E)75% of the maximum current.

Accepted Answer

The time constant in an RL circuit is the time it takes for the current to reach approximately 63% of its maximum value after the circuit is closed.

Question 7

In a given LC resonant circuit,
A)the stored electric field energy is greater than the stored magnetic field energy.
B)the stored electric field energy is less than the stored magnetic field energy.
C)the stored electric field energy is equal to the stored magnetic field energy.
D)all of the given answers are possible.

Accepted Answer

The answer of In a given LC resonant circuit,
A)the stored...

Question 8

Mutual inductance can depend upon
A)the shape of the coils.
B)the number of coils.
C)the number of turns.
D)the relative position of the coils.
E)all of the above as well as other factors.

Accepted Answer

Mutual inductance depends on factors such as the shape of the coils, the number of turns, and the relative position of the coils, among other factors.

Question 9

A resistor and an inductor are connected in series to a battery. The battery is suddenly removed from the circuit. The time constant for of the circuit represents the time required for the current to decrease to
A)25% of the original value.
B)37% of the original value.
C)50% of the original value.
D)63% of the original value.
E)75% of the original value.

Accepted Answer

The time constant in an RL circuit is the time it takes for the current to decrease to 37% (1/e) of its original value after the battery is removed.

Question 10

The inductive reactance of an inductor is higher at low frequencies.

Accepted Answer

The answer of The inductive reactance of an inductor is...

Question 11

The capacitive reactance is directly proportional to the frequency of the applied ac signal.

Accepted Answer

The answer of The capacitive reactance is directly proportional to...

Question 12

Starting from zero, an electric current is established in a circuit made of a battery of emf E, a resistor of resistance R and an inductor of inductance L. The electric current eventually reaches its steady-state value. What would be the effect of using a resistor with a higher resistance in this circuit?
A)The steady-state value of the current would be smaller, but it would take less time to reach it.
B)The steady-state value of the current would be larger, but it would take less time to reach it.
C)The steady-state value of the current would be smaller, but it would take more time to reach it.
D)The steady-state value of the current would be larger, but it would take more time to reach it.
E)The steady-state value of the current would be smaller, but it would take the same amount of time to reach it.

Accepted Answer

The answer of Starting from zero, an electric current is...

Question 13

The capacitive reactance increases with the capacitance.

Accepted Answer

The answer of The capacitive reactance increases with the capacitance....

Question 14

A series LRC circuit connected across an ac voltage source will have a positive value of the phase angle at high frequencies.

Accepted Answer

The answer of A series LRC circuit connected across an...

Question 15

When a charged capacitor is connected to an inductor, the value of the charge on the capacitor oscillates and so does the current in the circuit. What changes in the current would take place if the same capacitor, with the same initial charge, is connected to a inductor with a larger inductance?
A)Both the period of oscillation of the current and its maximum value would increase.
B)The period of oscillation of the current would stay the same but its maximum value would increase.
C)The period of oscillation of the current would decrease but its maximum value would remain the same.
D)The period of oscillation of the current would increase but its maximum value would remain the same.
E)Both the period of oscillation of the current and its maximum value would decrease.

Accepted Answer

The answer of When a charged capacitor is connected to...

Question 16

A resistor and an inductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the resistor is
A)greater than the battery's terminal voltage.
B)equal to the battery's terminal voltage.
C)less than the battery's terminal voltage, but not zero.
D)zero.

Accepted Answer

At the moment contact is made, the inductor initially opposes any change in current, so the current is zero. Therefore, the voltage across the resistor, which depends on current, is also zero.

Question 17

In a series LRC circuit a capacitor will be dominant at lower frequencies.

Accepted Answer

At lower frequencies, the capacitive reactance (Xc = 1/(2πfC)) is high, making the capacitor dominant in the circuit.

Question 18

Comparing the mutual inductance M₁₂ of coil 1 with respect to coil 2 with the mutual inductance M₂₁ of coil 2 with respect to coil 1, it turns out that A)M₂₁ is always greater. B)M₁₂ > M₂₁. C)M₁₂ < or = M₂₁. D)M₁₂ = M₂₁. E)M₁₂ is always greater.

Accepted Answer

The mutual inductance between two coils is a property of the pair and is the same regardless of the order, so M₁₂ = M₂₁.

Question 19

An ac signal of a certain frequency is applied to a capacitor. The current leads the voltage by 90°.

Accepted Answer

In a capacitor, the current leads the voltage by 90° in an AC circuit.

Question 20

The capacitive reactance of a capacitor is very small at low frequencies.

Accepted Answer

The capacitive reactance of a capacitor is inversely proportional to frequency, so it is actually very high at low frequencies.

Quiz 30: Inductance, Electromagnetic Oscillations, and Ac Circuits

In a series LRC circuit an inductor will be dominant at higher frequencies.

If the current increases in a solenoid, the induced emf acts to

A series LRC circuit connected across an ac voltage source has minimum current flowing through the circuit when operating at the resonant frequency.

A resistor and an inductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the inductor is

A resistor and an inductor are connected in series to a battery. The time constant for the circuit represents the time required for the current to reach

In a given LC resonant circuit,

Mutual inductance can depend upon

A resistor and an inductor are connected in series to a battery. The battery is suddenly removed from the circuit. The time constant for of the circuit represents the time required for the current to decrease to

The inductive reactance of an inductor is higher at low frequencies.

The capacitive reactance is directly proportional to the frequency of the applied ac signal.

The capacitive reactance increases with the capacitance.

A series LRC circuit connected across an ac voltage source will have a positive value of the phase angle at high frequencies.

When a charged capacitor is connected to an inductor, the value of the charge on the capacitor oscillates and so does the current in the circuit. What changes in the current would take place if the same capacitor, with the same initial charge, is connected to a inductor with a larger inductance?

A resistor and an inductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the resistor is

In a series LRC circuit a capacitor will be dominant at lower frequencies.

Comparing the mutual inductance M12 of coil 1 with respect to coil 2 with the mutual inductance M21 of coil 2 with respect to coil 1, it turns out that

An ac signal of a certain frequency is applied to a capacitor. The current leads the voltage by 90°.

The capacitive reactance of a capacitor is very small at low frequencies.

Comparing the mutual inductance M₁₂ of coil 1 with respect to coil 2 with the mutual inductance M₂₁ of coil 2 with respect to coil 1, it turns out that