Physics Worksheet - 11
Board: CBSE/ICSE/AHSEC
Topic(s): Electric Potential and Potential Energy
Total Marks: 20
Time: 30 minutes
Name: ____________________ Class: _______ Date: ___________
INSTRUCTIONS
• Answer all questions.
• Write neatly and legibly.
• For numerical problems, show your working and include units in your final answer.
• Use k = 8.99 × 10⁹ N m² C⁻² where required.
• Charge of an electron = -1.60 × 10⁻¹⁹ C.
• Charge of a proton = +1.60 × 10⁻¹⁹ C.
SECTION A: MULTIPLE CHOICE QUESTIONS
The definition of electric potential difference between two points is: (1 mark)
a) The force experienced per unit positive charge.
b) The work done in moving a unit positive charge between the points.
c) The product of the electric field and the distance between the points.
d) The total kinetic energy gained by a charge moving between the points.
The SI unit for electric potential is the Volt (V). This unit is equivalent to: (1 mark)
a) Newton per Coulomb (N/C)
b) Joule per Coulomb (J/C)
c) Coulomb per second (C/s)
d) Newton-metre (N m)
An electron is moved from point A to point B along an equipotential line. Which statement about the work done on the electron is correct? (1 mark)
a) The work done is positive.
b) The work done is negative.
c) The work done is zero.
d) The work done depends on the magnitude of the potential.
In a region of space, the electric field lines point in the positive x-direction. This indicates that: (1 mark)
a) The electric potential is constant along the x-axis.
b) The electric potential increases in the positive x-direction.
c) The electric potential decreases in the positive x-direction.
d) The electric potential is zero everywhere.
Two positive charges, +q and +2q, are separated by a distance r, resulting in a positive potential energy U. If the charge +2q is replaced by a charge -2q at the same position, the new potential energy of the system will be: (1 mark)
a) -2U
b) -U
c) +2U
d) Zero
SECTION B: NUMERICAL PROBLEMS
Calculate the work done in moving a charge of +4.0 µC through a potential difference of 12 V. (3 marks)
What is the electric potential at a distance of 0.50 m from a point charge of +2.5 nC? (3 marks)
Two large parallel plates are separated by 2.0 cm and have a potential difference of 100 V between them. Calculate the work done when a proton is moved from the negative plate to the positive plate. (3 marks)
An electron is brought from a very large distance (infinity) to a point 0.25 m away from a fixed charge of +5.0 µC. What is the change in electric potential energy of the electron-charge system? (3 marks)
Two point charges, Q₁ = +3.0 nC and Q₂ = -5.0 nC, are located on the x-axis at x = 0 m and x = 4.0 m, respectively. Find the point on the x-axis between the two charges where the net electric potential is zero. (3 marks)