Question 1

Consider the group of charges in this figure. All three charges have Q = 2.4 nC. What is their electric potential energy? A) 4.1 × 10^-6 J B) 4.6 × 10^-6 J C) 4.2 × 10^-6 J D) 4.4 × 10^-6 J

Accepted Answer

4.1 × 10^-6 J

Question 2

A 100.0 pF capacitor consists of two circular plates of radius 0.40 mm. How far apart are the plates? (The value of ?_o is 8.85 × 10^-12 C²/N · m².) A) 0.044 ?m B) 0.022 ?m C) 0.0050 ?m D) 0.0025 ?m

Accepted Answer

The capacitance of a parallel-plate capacitor is given by:$$C = \frac{\epsilon_0 A}{d}$$where:* C is the capacitance in farads (F)* $\epsilon_0$ is the permittivity of free space (8.85 × 10^-12 C^2/N · m^2)* A is the area of each plate in square meters (m^2)* d is the distance between the plates in meters (m)We are given the following information:* C = 100.0 pF = 100.0 × 10^-12 F* r = 0.40 mm = 0.40 × 10^-3 m* A = πr^2 = π(0.40 × 10^-3 m)^2 = 5.03 × 10^-7 m^2We can use the above equation to solve for d:$$d = \frac{\epsilon_0 A}{C} = \frac{(8.85 × 10^-12 C^2/N · m^2)(5.03 × 10^-7 m^2)}{100.0 × 10^-12 F} = 0.044 μm$$Therefore, the correct answer is A) 0.044 μm.

Question 3

A uniform electric field has the strength of 5.0 N/C. What is the electric energy density of the field? (The value of?_o is 8.85 × 10^-12 C²/N · m².) A) 1.1 × 10^-10 J/m³ B) 2.2 × 10^-11 J/m³ C) 1.4 × 10¹² J/m³ D) 2.8 × 10¹² J/m³

Accepted Answer

The electric energy density of a uniform electric field is given by the equation u = (1/2)ε_oE², where ε_o is the permittivity of free space and E is the electric field strength. Substituting the given values into the equation, we get u = (1/2)(8.85 × 10^-12 C²/N · m²)(5.0 N/C)² = 1.1 × 10^-10 J/m³.

Question 4

Suppose a region of space has a uniform electric field, directed toward the right, as shown in the figure. Which statement is true?  &#10;A) The voltage at all three locations is the same.&#10;B) The voltage at points A and B are equal, and the voltage at point C is higher than the voltage at point A.&#10;C) The voltage at points A and B are equal, and the voltage at point C is lower than the voltage at point A.&#10;D) The voltage at point A is the highest, the voltage at point B is the second highest, and the voltage at point C is the lowest.&#10;E) None of the above

Accepted Answer

The answer of Suppose a region of space has a...

Question 5

A wire has a current of 6.0 mA in it. How many electrons pass a given point in a minute? A) 2.3 × 10¹⁸ B) 360 C) 6.3 × 10¹⁴ D) 5.4 × 10^-15

Accepted Answer

The current is 6.0 mA, which is 6.0 × 10^-3 A. The charge of one electron is approximately 1.6 × 10^-19 C. The number of electrons passing a point per second is given by the current divided by the charge of an electron. In one minute (60 seconds), the number of electrons is (6.0 × 10^-3 C/s) × (60 s) / (1.6 × 10^-19 C/electron) = 2.25 × 10^18 electrons, which is approximately 2.3 × 10^18 electrons.

Question 6

Each of the resistors in the circuit shown have a resistance of 160.0 ?. What is the equivalent resistance of the circuit?  &#10;A) 400.0 ?&#10;B) 640.0 ?&#10;C) 480.0 ?&#10;D) 160.0 ?

Accepted Answer

The answer of Each of the resistors in the circuit...

Question 7

Refer to the figure shown. What is the current through the 4.0 ? resistor?  &#10;A) 1.5 A&#10;B) 4.0 A&#10;C) 0.43 A&#10;D) 1.1 A

Accepted Answer

The answer of Refer to the figure shown. What is...

Question 8

A 10.0 V battery is connected across two resistors in series. If the resistors have resistances of 840.0 ? and 590.0 ? , what is the voltage drop across the 590.0 ? resistor?&#10;A) 4.1 V&#10;B) 5.9 V&#10;C) 14 V&#10;D) 7.0 V

Accepted Answer

The total resistance is 1430.0 ?. The current is 10.0 V / 1430.0 ? = 0.006993 A. The voltage drop across the 590.0 ? resistor is 0.006993 A * 590.0 ? = 4.1 V.

Question 9

An electron in a magnetic field has a cyclotron frequency of 8.0 × 10¹² Hz. What is the magnetic field strength? (The mass of an electron is 9.1 × 10^-31 kg, and the charge of an electron is 1.6 × 10^-19 C.)

A) 290 T
B) 4.5 T
C) 0.22 T
D) 0.0035 T

Accepted Answer

The cyclotron frequency is given by:$$f_c = \frac{qB}{2\pi m}$$where:* $$f_c$$ is the cyclotron frequency* $$q$$ is the charge of the electron* $$B$$ is the magnetic field strength* $$m$$ is the mass of the electronSolving for $$B$$, we get:$$B = \frac{2\pi m f_c}{q}$$Plugging in the given values, we get:$$B = \frac{2\pi (9.1 	imes 10^{-31} 	ext{ kg})(8.0 	imes 10^{12} 	ext{ Hz})}{1.6 	imes 10^{-19} 	ext{ C}} = 0.22 	ext{ T}$$Therefore, the correct answer is C) 0.22 T.

Question 10

A rigid rectangular loop, which measures 0.30 m by 0.40 m, carries a current of 5.5 A, as shown. A uniform external magnetic field of magnitude 2.9 T in the negative x-direction is present. Segment CD is in the x-z plane and forms a 35° angle with the z-axis, as shown. An external torque applied to the loop keeps it in static equilibrium. The magnitude of the external torque is closest to:

A) 1.1 N ? m
B) 0.73 N ? m
C) 1.3 N ? m
D) 1.4 N ? m
E) 1.6 N ? m

Accepted Answer

The answer of   A rigid rectangular loop, which...

Question 11

A very long wire generates a magnetic field of 0.0050 × 10^-4 T at a distance of 3.0 mm. What is the magnitude of the current? A) 7.5 mA B) 1.7 mA C) 3300 mA D) 24,000 mA

Accepted Answer

The answer of A very long wire generates a magnetic...

Question 12

A rigid rectangular loop, which measures 0.30 m by 0.40 m, carries a current of 9.9 A, as shown. A uniform external magnetic field of magnitude 1.8 T in the negative x-direction is present. Segment CD is in the x-z plane and forms a 19° angle with the z-axis, as shown. The y-component of the magnetic force on segment AB is closest to:

A) +5.1 N
B) -5.1 N
C) +1.7 N
D) -1.7 N
E) zero

Accepted Answer

The answer of   A rigid rectangular loop, which...

Question 13

A horseshoe magnet has straight sides as shown. An electron travelling directly at the north pole is deflected. Why?&#10;

Accepted Answer

The answer of A horseshoe magnet has straight sides as...

Question 14

A long straight wire has a constant current flowing to the right. A square ring is situated above the wire, and also has a constant current flowing through it (as shown). Which of the following statements is true?

A) The net magnetic force on the ring is upward, and there is also a net torque on the ring.
B) The net magnetic force on the ring is zero, and the net torque is zero.
C) The net magnetic force on the ring is downward, and there is also a net torque on the ring.
D) The net magnetic force on the ring is zero, but there is a net torque on the ring.
E) The net magnetic force on the ring is downward, and the net torque is zero.

Accepted Answer

The answer of A long straight wire has a constant...

Deck 5: Electric Energy, Potential, Capacitors, Electric Current, Resistance, Circuits, Magnetic Fields and Forces