Exam 17: Electric Potential

An air-filled parallel plate capacitor is attached to a voltage source and charged. The voltage source is removed, and then the plates are separated to double their previous distance. What happens to the electric field between the plates when the plates are separated?

The capacitance of a parallel plate capacitor changes when a dielectric is inserted between the plates. This is mainly due to

Three point charges, q₁ = 2.0 μC, q₂ = 2.0 μC, and q₃ = −1.0 μC, are located at the vertices of an equilateral triangle of side length 30 cm. What is the potential energy of this arrangement?

If the plate area, plate separation, dielectric strength, and dielectric constant all are doubled for a parallel plate capacitor, what happens to the maximum voltage before breakdown occurs for this capacitor?

If helium nuclei and protons are each accelerated from rest through the same potential difference, how do the resulting speeds compare?

Doubling both charges changes the potential energy for a pair of point charges by a factor of

If helium nuclei and protons are each accelerated from rest through the same potential difference V, which gets the greatest kinetic energy and by what factor is it greater?

If 500 electrons are placed on a conducting sphere of radius 10 μm, what is the potential at the surface of the sphere?

Three 1.0 μC charges are placed along the x-axis, one charge at x = −10 cm, another at the origin, and the last one at x = 10 cm. What is the total potential energy of this arrangement?

To store 80 mJ of energy in a 100 μF capacitor, what voltage is necessary?

A pair of parallel conducting plates have potentials of −17 V and 55 V, respectively. An electron is ejected from the plate at potential −17 V and travels to the plate at 55 V. What is the change in the electron's potential energy as it makes this journey?

Which of the following statements is true?

One member of a pair of parallel conducting plates has potential 17 V. An electron is ejected from that plate and travels the other plate, attaining a velocity of 5.0 × 10⁶ m/s in the process. What is the potential of the second plate? The mass of the electron is 9.11 × 10⁻³¹ kg.

An air-filled parallel plate capacitor is attached to a voltage source and charged. The voltage source is removed, and then the plates are separated to double their previous distance. What happens to the potential difference between the plates when they are separated?

If the potential difference across the plates of a capacitor is doubled, what happens to the energy stored?

What is the force on a proton sitting midway between a pair of parallel conducting plates that are at potentials of −17 V and 55 V, respectively? Their separation distance is 1.5 cm.

Three point charges, q₁, q₂, and q₃, are arranged so the potential energy for the pair q₁ and q₂ is 0.12 J and for the pair q₂ and q₃ is 0.23 J. What is the potential energy for the pair q₁ and q₃?

A hollow conducting sphere of radius 12 cm has a net charge of 18 μC. What is the potential 20 cm from the center of the sphere?

A parallel plate capacitor has air between the plates, which are circular with radius 0.07 m. The separation gap is 0.375 mm. What is the maximum energy that can be stored in this capacitor if air-breakdown is to be avoided? The breakdown threshold field is approximately 3 × 10⁶ N/C.

At a given location in space, the potential is known to be greater when one moves in any direction. To be more specific, no matter which direction one goes, a small step in that direction results in an increase in the potential. This means that the electric field at this location is