Exam 21: Electric Potential

Consider a uniform horizontal electric field of 50 N/C directed toward the east. If the electric potential measured at a given point is 80 V, what is the potential at a point 1.0 m directly west of that point?

The equipotential surfaces for two point charges are shown in the figure, with the value of potential marked on the line for each surface. (a) What is the potential difference, V_G - V_D, between points G and D? (b) What is the potential difference, V_A - V_G, between points A and G?

Point charges +4.00 μC and +2.00 μC are placed at the opposite corners of a rectangle as shown in the figure. If these charges are released and are free to move with no friction, what is the maximum amount of kinetic energy they will gain? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

If the result of your calculation of a quantity has SI units of kg ∙ m/(s² ∙C), that quantity could be

A tiny particle carries a charge of $6.0 \mu \mathrm { C }$ What is the energy density in the electric field at a distance of $4.0 \mathrm {~m}$ from this charge? (ε₀ = 8.85 × 10^-12 C²/N ∙ m², k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Which of the following changes will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice.)

Each plate of a parallel-plate air-filled capacitor has an area of 0.0040 $m ^ { 2 }$ , and the separation of the plates is $0.020 \mathrm {~mm}$ An electric field of $8.2 \times 10^6 \mathrm {~N} / \mathrm { C }$ is present between the plates. What is the energy density in the region between the plates? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

If it takes 50 J of energy to move 10 C of charge from point A to point B, what is the magnitude of the potential difference between points A and B?

An ideal air-filled parallel plate capacitor with plate a separation of 4.0 cm has a plate area of 0.040 m². What is the capacitance of this capacitor with air between these plates? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

Three point charges, -2.00 μC, +4.00 μC, and +6.00 μC, are located along the x-axis as shown in the figure. What is the electric potential (relative to infinity) at point P due to these charges? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

An electric dipole with ±5.0 μC point charges is positioned so that the positive charge is $1.0 \mathrm {~mm}$ to the right of the origin and the negative charge is at the origin. How much work does it take to bring a $3.0 - \mu \mathrm { C }$ point charge from very far away to the point x = 3.0 mm, y = 0.0 mm? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

A uniform electric field has the strength of $7.0 \mathrm {~N} / \mathrm { C }$ What is the electric energy density of this field? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

If an electron is accelerated from rest through a potential difference of 1500 V, what speed does it reach? (e = 1.60 × 10^-19 C , m_electron = 9.11 × 10^-31 kg)

An air-filled parallel-plate capacitor is constructed with a plate area of 0.40 m² and a plate separation of 0.10 mm. It is then charged to a potential difference of 12 V? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²) (a) How much charge is stored on each of its plates? (b) How much energy is stored in it?

When a 6.00-μF air-filled capacitor has a charge of ±40.0 μC on its plates, how much potential energy is stored in this capacitor?

A 25.0-V potential source (a battery) is connected across the plates of a 6.66-µF air-filled parallel-plate capacitor having plates that are 1.22 mm apart. What energy density does it produce between the plates? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

How much work must we do on an electron to move it from point A, which is at a potential of +50V, to point B, which is at a potential of -50 V, along the semicircular path shown in the figure? Assume the system is isolated from outside forces. (e = 1.60 × 10^-19C)

Which statements must be true about the surface of a charged conductor in which no charge is moving? (There could be more than one correct choice.)

The square plates of a 5000-pF parallel-plate capacitor measure 50 mm by 50 mm and are separated by a dielectric that is $0.23 \mathrm {~mm}$ thickand totally fills the region between the plates. The voltage rating (the maximum safe voltage) of the capacitor is $400 \mathrm {~V}$ What is the maximum energy that can be stored in this capacitor without damaging it? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

A sphere with radius 2.0 mm carries a $+ 2.0 \mu \mathrm { C }$ charge. What is the potential difference, $V _ { B } - V _ { A }$ between point B, which is $4.0 \mathrm {~m}$ from the center of the sphere, and point A, which is $6.0 \mathrm {~m}$ from the center of the sphere? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)