Question 1

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the power output delivered by the emf of the battery?
A)0.21 W
B)5.57 W
C)5.78 W
D)6.00 W

Accepted Answer

Using Ohm's Law, we can find the resistance of the circuit:

R = V/I = 12V / 0.482A = 24.9 ohms

This is slightly different than the given 24.0 ohm resistor, which could be due to rounding or measurement error. Regardless, we can still use this calculated resistance to find the power output of the emf:

P = VI = (12V)(0.482A) = 5.78 W

Therefore, the correct answer is C) 5.78 W.

Question 2

Three 8.0-W resistors are connected in parallel.What is their equivalent resistance?
A)0.054 W
B)0.13 W
C)0.38 W
D)2.7 W

Accepted Answer

When resistors are connected in parallel, the reciprocal of the equivalent resistance is the sum of the reciprocals of the individual resistances. For three 8.0-ohm resistors in parallel, 1/R_eq = 1/8 + 1/8 + 1/8 = 3/8, so R_eq = 8/3 = 2.67 ohms, which rounds to 2.7 ohms.

Question 3

Three resistors connected in series each carry currents labeled I₁,I₂ and I₃.Which of the following expresses the value of the total current I_T in the system made up of the three resistors in series? A)I_T = I₁ + I₂ + I₃ B)I_T = (1/I₁ + 1/I₂+ 1/I₃) C)I_T = I₁ = I₂ = I₃ D)I_T = (1/I₁ + 1/I₂+ 1/I₃)^-1

Accepted Answer

In a series circuit, the current flowing through each resistor is the same. Therefore, the total current $I_{T}$ is equal to the current through each resistor ($I_{1} = I_{2} = I_{3}$).

Question 4

If R₁ < R₂ < R₃,and if these resistors are connected in series in a circuit,which one dissipates the greatest power? A)R₁ B)R₂ C)R₃ D)All are equal in power dissipation.

Accepted Answer

The power dissipated in a resistor is given by P=I^2R, where I is the current flowing through the resistor and R is the resistance of the resistor. Since all three resistors are in series, the current flowing through each resistor is the same. Therefore, the resistor with the highest resistance (R₃) will dissipate the greatest power as P=I^2R and the resistance (R) is the highest.

Question 5

Which resistor is in series with resistor R? A)R₁ B)R₂ C)R₃ D)R₄

Accepted Answer

The answer of Which resistor is in series with resistor...

Question 6

When a light bulb is turned on,its resistance increases until it reaches operating temperature.What happens to the current in the bulb as it is warming up?
A)It stays constant.
B)It increases.
C)It decreases.
D)It increases at first and then decreases.

Accepted Answer

When the resistance of the bulb increases, according to Ohm's Law, as the voltage is constant, the current must decrease. Therefore, the current in the bulb decreases as it warms up.

Question 7

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the resulting terminal voltage of the battery?
A)0.4 V
B)5.8 V
C)11.6 V
D)12.0 V

Accepted Answer

The terminal voltage is calculated using Ohm's Law (V = IR). The current is 482 mA (or 0.482 A), and the resistance is 24.0 ohms. V = 0.482 A * 24.0 ohms = 11.568 V, which rounds to 11.6 V.

Question 8

The internal resistances of an ideal voltmeter and an ideal ammeter are respectively (ideal meaning the behavior of the system is not changed when using the meter):
A)zero and zero.
B)infinite and infinite.
C)zero and infinite.
D)infinite and zero.

Accepted Answer

An ideal voltmeter has infinite internal resistance to ensure it does not draw any current from the circuit it is measuring, thus not affecting the circuit's operation. An ideal ammeter has zero internal resistance to ensure it does not add any resistance to the circuit it is measuring, thus not affecting the circuit's operation.

Question 9

Three resistors connected in series have individual voltages labeled DV₁,DV₂ and DV₃,respectively.Which of the following expresses the value of the total voltage DV_T taken over the three resistors together? A)DV_T = DV₁+ DV₂ + DV₃ B)DV_T = (1/DV₁ + 1/DV₂ + 1/DV₃) C)DV_T = DV₁ = DV₂= DV₃ D)DV_T = (1/DV₁ + 1/DV₂ + 1/DV₃)^-1

Accepted Answer

In a series circuit, the total voltage is equal to the sum of the individual voltages across each resistor. Therefore, the correct expression for the total voltage is DV_T = DV₁ + DV₂ + DV₃. Option A is the only expression that matches this rule. Option B is the formula for the equivalent resistance of resistors in parallel, not in series. Option C states that the voltage across each resistor is the same, which is only true for resistors in parallel. Option D is an incorrect formula that contains a random multiplication and subtraction operation.

Question 10

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the internal resistance of the battery?
A)0.02 W
B)0.9 W
C)25.0 W
D)49.8 W

Accepted Answer

Using Ohm's law, we can find the total resistance: 
R_total = V / I = 12.0 V / 0.482 A = 24.9 ohms

Then, using the formula for total resistance of a circuit: 
R_total = R_internal + R_external 
we can solve for the internal resistance: 
R_internal = R_total - R_external = 24.9 ohms - 24.0 ohms = 0.9 ohms

So, the answer is B) 0.9 ohms.

Question 11

Resistors of values 8.0 W,12.0 W,and 24.0 W are connected in series across a battery with a small internal resistance.Which resistor dissipates the greatest power?
A)the 8.0-W resistor
B)the 12.0-W resistor
C)the 24.0-W resistor
D)The answer depends on the internal resistance of the battery.

Accepted Answer

The power dissipated by a resistor in a series circuit is given by P = V^2/R, where V is the voltage across the resistor and R is its resistance. In a series circuit, the same current flows through each resistor, but the voltage across each resistor depends on its resistance. Since the voltage drop across the series combination of resistors is equal to the battery voltage, the largest voltage drop will occur across the largest resistor. Therefore, the 24.0-W resistor will dissipate the greatest power, followed by the 12.0-W resistor and then the 8.0-W resistor.

Question 12

Three 8.0-W resistors are connected in series.What is their equivalent resistance?
A)24.0 W
B)8.0 W
C)0.38 W
D)0.13 W

Accepted Answer

When resistors are connected in series, their resistances add up. Therefore, the equivalent resistance is 8.0 W + 8.0 W + 8.0 W = 24.0 W.

Question 13

The two ends of a 3.0-W resistor are connected to a 9.0-V battery.What is the current through the resistor?
A)27 A
B)6.3 A
C)3.0 A
D)0.33 A

Accepted Answer

We can use Ohm's Law to calculate the current through the resistor:

I = V/R

where I is the current, V is the voltage, and R is the resistance.

Plugging in the values given in the problem, we get:

I = 9.0 V / 3.0 Ω = 3.0 A

Therefore, the answer is choice C.

Question 14

Three resistors,each with resistance R₁,are in series in a circuit.They are replaced by one equivalent resistor,R.Comparing this resistor to the first resistor of the initial circuit,which of the following is true? A)The current through R equals the current through R₁. B)The voltage across R equals the voltage across R₁. C)The power given off by R equals the power given off by R₁. D)R is less than R₁.

Accepted Answer

When resistors are in series, the same current flows through each resistor. Therefore, the current through the equivalent resistor R is the same as the current through each of the original resistors, R₁.

Question 15

Three resistors with values of R₁,R₂ and R₃,respectively,are connected in series.Which of the following expresses the total resistance,R_T,of the three resistors? A)R_T = R₁ + R₂ + R₃ B)R_T = (1/R₁ + 1/R₂ + 1/R₃) C)R_T= R₁ = R₂ = R₃ D)R_T = (1/R₁ + 1/R₂+ 1/R₃)^-1

Accepted Answer

When resistors are connected in series, their resistances add up to give the total resistance of the circuit. Therefore, the correct expression for the total resistance of the three resistors in series is R_T = R₁ + R₂ + R₃, which is choice A. Choice B represents the formula for calculating the total resistance of resistors in parallel, not in series. Choice C is not an expression for the total resistance, but rather states that all three resistors have the same resistance value. Choice D is a slightly modified version of the formula for total resistance in parallel, but with the term (^-1) added, which does not make sense in this context.

Question 16

Three 4.0-W resistors are connected in parallel to a 12.0-V battery.What is the current in any one of the resistors?
A)16 A
B)9.0 A
C)3.0 A
D)48 A

Accepted Answer

The total resistance of the three resistors in parallel can be calculated using the formula:

1/R(total) = 1/R1 + 1/R2 + 1/R3

Substituting the values, we get:

1/R(total) = 1/4.0 + 1/4.0 + 1/4.0
1/R(total) = 3/4.0
R(total) = 4/3.0 = 1.33 Ω

Now, using Ohm's Law, we can calculate the current in any one of the resistors:

I = V/R
I = 12.0 V/4.0 Ω
I = 3.0 A

Therefore, the current in any one of the resistors is 3.0 A, which is option C.

Question 17

The two ends of a 3.0-W resistor are connected to a 9.0-V battery.What is the total power delivered by the battery to the circuit?
A)3.0 W
B)27 W
C)0.33 W
D)0.11 W

Accepted Answer

The total power delivered by the battery to the circuit can be calculated using the formula P = V^2/R, where P is power, V is voltage, and R is resistance.

In this case, V = 9.0 V and R = 3.0 Ω.

Plugging these values into the formula, we get:

P = (9.0 V)^2 / 3.0 Ω = 81.0 / 3.0 = 27.0 W

Therefore, the total power delivered by the battery to the circuit is 27.0 W, which corresponds to choice B).

Question 18

Three resistors,with values of 2.0,4.0 and 8.0 W,respectively,are connected in series.What is the overall resistance of this combination?
A)0.58 W
B)1.1 W
C)7.0 W
D)14.0 W

Accepted Answer

When resistors are connected in series, the total resistance is the sum of the individual resistances: 2.0 + 4.0 + 8.0 = 14.0 W.

Question 19

The basic function of an electromotive force in a circuit is to do which of the following?
A)Convert electrical energy into some other form.
B)Convert some other form of energy into electrical.
C)Both choices (a)and (b)are valid.
D)None of the above choices are valid.

Accepted Answer

The basic function of an electromotive force in a circuit is to convert some other form of energy (such as chemical, mechanical, or light energy) into electrical energy, which then flows through the circuit. It does not convert electrical energy into some other form, so choice A is not valid. Choice C is also not valid as only option B is correct. Choice D is incorrect because the question does have a valid answer.

Question 20

Which voltage is not caused by a source of emf?
A)the voltage across a charged capacitor
B)the voltage across two copper-iron junctions at different temperatures
C)the voltage across the terminals of a dry cell battery
D)the voltage from an electric generator

Accepted Answer

The voltage across a charged capacitor is not caused by a source of emf, but rather by the storage of electrical energy due to the separation of charges on the plates of the capacitor. The other options (B, C, D) are all examples of sources of emf.

Quiz 18: Direct-Current Circuits

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the power output delivered by the emf of the battery?

Three 8.0-W resistors are connected in parallel.What is their equivalent resistance?

Three resistors connected in series each carry currents labeled I₁,I₂ and I₃.Which of the following expresses the value of the total current I_T in the system made up of the three resistors in series?

If R₁ < R₂ < R₃,and if these resistors are connected in series in a circuit,which one dissipates the greatest power?

Which resistor is in series with resistor R?

When a light bulb is turned on,its resistance increases until it reaches operating temperature.What happens to the current in the bulb as it is warming up?

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the resulting terminal voltage of the battery?

The internal resistances of an ideal voltmeter and an ideal ammeter are respectively (ideal meaning the behavior of the system is not changed when using the meter) :

Three resistors connected in series have individual voltages labeled DV₁,DV₂ and DV₃,respectively.Which of the following expresses the value of the total voltage DV_T taken over the three resistors together?

When a 24.0-W resistor is connected across a 12.0-V battery,a current of 482 mA flows.What is the internal resistance of the battery?

Resistors of values 8.0 W,12.0 W,and 24.0 W are connected in series across a battery with a small internal resistance.Which resistor dissipates the greatest power?

Three 8.0-W resistors are connected in series.What is their equivalent resistance?

The two ends of a 3.0-W resistor are connected to a 9.0-V battery.What is the current through the resistor?

Three resistors,each with resistance R₁,are in series in a circuit.They are replaced by one equivalent resistor,R.Comparing this resistor to the first resistor of the initial circuit,which of the following is true?

Three resistors with values of R₁,R₂ and R₃,respectively,are connected in series.Which of the following expresses the total resistance,R_T,of the three resistors?

Three 4.0-W resistors are connected in parallel to a 12.0-V battery.What is the current in any one of the resistors?

The two ends of a 3.0-W resistor are connected to a 9.0-V battery.What is the total power delivered by the battery to the circuit?

Three resistors,with values of 2.0,4.0 and 8.0 W,respectively,are connected in series.What is the overall resistance of this combination?

The basic function of an electromotive force in a circuit is to do which of the following?

Which voltage is not caused by a source of emf?