Exam 16: The Electric Field

Two point charges of +2.00 μC and +4.00 μC are at the origin and at the point x = 0.000 m,y = -0.300 m,as shown in the figure.What is the electric potential due to these charges,relative to infinity,at the point P at x = 0.400 m on the x-axis? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A space probe approaches a planet,taking measurements as it goes.If it detects a potential difference of 6000 MV between the altitudes of 253,000 km and 276,000 km above the planet's surface,what is the approximate electric field strength produced by the planet at 264,500 km above the surface? Assume the $\vec { E }$ field is approximately constant at these altitudes.

A conductor is placed in a steady external electric field.Which of the following statements are correct for this situation? (There could be more than one correct choice.)

When the magnitude of the charge on each plate of an air-filled capacitor is 4 μC,the potential difference between the plates is 80 V.What is the capacitance of this capacitor?

A parallel-plate capacitor consists of a set of two parallel plates of area A separated by a distance d.This capacitor is connected to a battery that maintains a constant potential difference across the plates.A slab of a dielectric material is inserted in the region between the plates and completely fills it.What changes would you observe as the dielectric is inserted? (There could be more than one correct choice.)

When a 12.0-V battery causes 2.00 μC of charge to flow onto the plates of an air-filled capacitor,how much work did the battery do?

Which of the following will increase the capacitance of a parallel-plate capacitor? (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)

An ideal,isolated,air-filled parallel-plate capacitor is not connected to a battery but has equal and opposite charges of 3.9 nC on its plates.The separation between the plates initially is 1.2 mm,and for this separation the capacitance is 3.1 × 10^-11 F.How much work must be done to pull the plates apart until their separation becomes 7.7 mm? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

An ideal parallel-plate capacitor consists of two parallel plates of area A separated by a distance d.This capacitor is connected across a battery that maintains a constant potential difference between the plates.If the separation between the plates is now doubled,the magnitude of the charge on the plates will

At a distance d from a point charge Q,the energy density in its electric field is u.If we now go to a distance d/2 from the charge,what is the energy density at the new location?

The figure shows two unequal charges,+q and -Q.Charge -Q has greater magnitude than charge +q.Point X is midway between the charges.In what section of the line will there be a point where the resultant $\vec { E }$ field is zero?

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)

Three equal-magnitude point charges of varying signs are placed at the corners of a square of side d as shown in the figure.Which one of the arrows shown represents the direction of the net $\vec { E }$ field at the center of the square?

The electron-volt is a unit of

A +4.0-μC and a -4.0-μC point charge are placed as shown in the figure.What is the potential difference between points A and B? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

An ideal parallel-plate capacitor consists of two parallel plates of area A separated by a distance d.This capacitor is connected to a battery and charged until its plates carry charges +Q and -Q,and the battery is then disconnected.If the separation between the plates is now doubled,the electrical energy stored in the capacitor will

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)

An air-filled capacitor has a potential difference between the plates of 80 V.If the charge on each of the plates of the capacitor has magnitude 8.0 μC,what is the electrical energy stored by this capacitor?

As an electron moves in the direction the $\vec { E }$ field lines