Electric Potential

When a charge of 3 C is moved from infinity to a point X in an electric field, the work done is 15 J. What is the electric potential at X?

• 45 V

• 22.5 V

• 15 V

• 5 V

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-2

In the direction of an electric field line, which of the following must be true?

• the electric field strength must increase

• the electric field strength must decrease

• the potential must increase

• the potential must decrease

Which statement about electric potential at a point must be correct?

• The potential is given by the rate of change of electric field strength with distance

• the potential is defined as the work done per unit positive charge in moving one electron from the point to infinity

• alternative units for electric potential are the joule and the volt

• the potential due to a system of point charges is given by the sum of the potentials due to the individual charges

The given diagram shows four identical point charges arranged at the corners of a square. What are the values of the electric field strength E and the electric potential V at point X in the middle of the square?

• A

• B

• C

• D

The given diagram shows charges of +2 µC and -2 µC situated at points P and Q respectively. Point X is midway between P and Q.

What is the direction of the electric field and the value of the electric potential at point X?

• A

• B

• C

• D

The given diagram shows a pair of large plane parallel conducting plates situated 40 mm apart. The potential difference between the plates is V.

Which of the following is the potential difference between point X and point Y?

• 15 / 40 V

• 25 / 40 V

• 20 / 40 V

• 40 / 40 V

The terms 'electric field strength', 'electric potential' and 'potential gradient' are often used in discussing electric fields. Which of the following statements about these terms is correct?

• Electric field strength at a point is the work done in bringing unit positive charge from infinity to the point

• Electric potential and potential gradient are both scalar quantities

• The potential gradient at a point is numerically equal to the electric field strength at that point.

• Unit potential gradient exists between any two points, if one joule of work is done in transporting one coulomb of charge between the points

A uniform electric field has lines of equal potential that are spaced 2.0 cm apart, as shown.

A charge of +5.0 µC is placed in the field.

Which of the following is the value of the electric force exerted on the charge?

• 6.0 x 10^-6 N

• 1.5 x 10^-2 N

• 3.0 x 10³ N

• 6.0 x 10⁵ N

A uniform electric field exists between two parallel charged plates 0.02 m apart. The given diagram shows how the potential energy Ep of an electron varies with displacement x from one of the plates.

Which of the following is the force on the electron?

• 1.2 x 10^-33 N

• 6.0 x 10^-32 N

• 7.5 x 10^-17 N

• 7.5 x 10^-15 N

The given table shows the electric potential V measured at various distances x from P along a line PQ.

At x = 0.040 m, what is the component along PQ of the electric field?

• 75 V m^-1 towards P

• 300 V m^-1 towards Q

• 300 V m^-1 towards P

• 450 V m^-1 towards Q