Physics 5C Exam 2 – Spring 2026 Version A
Physics 5C: Electricity, Magnetism, and Modern
Physics
Exam 2 – Spring 2026
Version A
Name: UID:
Time limit: 75 minutes.
Closed book; no notes. Formula sheet provided separately.
Calculator allowed (scientific or graphing). No phones, smartwatches, or devices with com-
munication capabilities.
Express all numerical answers in SI units. Include units with your answers.
Part I (Multiple Choice): Write the letter of your answer in the box provided.
Part II (Free Response): Show all work for full credit. Box your final answers with units
(for numerical answers) or in terms of the given variables (for symbolic answers).
Section Points Score
Part I: Multiple Choice (10 × 4) 40
Part II: Free Response 1 30
Part II: Free Response 2 30
Total 100
1
, Physics 5C Exam 2 – Spring 2026 Version A
Part I: Multiple Choice (10 questions, 4 points each, 40 points total)
For each multiple-choice question, write the letter of your answer (A, B, C, or D) in the box below
the question.
1. (4 points) A solid metal sphere carries a net positive charge. What is the electric field inside
the sphere?
A. Zero
B. Points radially inward
C. Points radially outward
D. Depends on the amount of charge
Answer:
Solution: A. In electrostatic equilibrium, the electric field inside a conductor is zero. All
excess charge resides on the surface. Distractors: (B) and (C) assume a field exists inside;
(D) thinks the answer depends on the charge magnitude.
2. (4 points) A conducting sphere of radius R carries charge +Q. The electric potential at the
surface is V0 . What is the electric potential at the center of the sphere?
A. Zero
B. V0 /2
C. V0
D. Infinity
Answer:
Solution: C. A conductor in electrostatic equilibrium is an equipotential; the potential
everywhere inside equals the potential at the surface. Distractors: (A) confuses E = 0
with V = 0; (B) assumes linear decrease; (D) applies V = kQ/r with r → 0 inside the
conductor.
2
Physics 5C: Electricity, Magnetism, and Modern
Physics
Exam 2 – Spring 2026
Version A
Name: UID:
Time limit: 75 minutes.
Closed book; no notes. Formula sheet provided separately.
Calculator allowed (scientific or graphing). No phones, smartwatches, or devices with com-
munication capabilities.
Express all numerical answers in SI units. Include units with your answers.
Part I (Multiple Choice): Write the letter of your answer in the box provided.
Part II (Free Response): Show all work for full credit. Box your final answers with units
(for numerical answers) or in terms of the given variables (for symbolic answers).
Section Points Score
Part I: Multiple Choice (10 × 4) 40
Part II: Free Response 1 30
Part II: Free Response 2 30
Total 100
1
, Physics 5C Exam 2 – Spring 2026 Version A
Part I: Multiple Choice (10 questions, 4 points each, 40 points total)
For each multiple-choice question, write the letter of your answer (A, B, C, or D) in the box below
the question.
1. (4 points) A solid metal sphere carries a net positive charge. What is the electric field inside
the sphere?
A. Zero
B. Points radially inward
C. Points radially outward
D. Depends on the amount of charge
Answer:
Solution: A. In electrostatic equilibrium, the electric field inside a conductor is zero. All
excess charge resides on the surface. Distractors: (B) and (C) assume a field exists inside;
(D) thinks the answer depends on the charge magnitude.
2. (4 points) A conducting sphere of radius R carries charge +Q. The electric potential at the
surface is V0 . What is the electric potential at the center of the sphere?
A. Zero
B. V0 /2
C. V0
D. Infinity
Answer:
Solution: C. A conductor in electrostatic equilibrium is an equipotential; the potential
everywhere inside equals the potential at the surface. Distractors: (A) confuses E = 0
with V = 0; (B) assumes linear decrease; (D) applies V = kQ/r with r → 0 inside the
conductor.
2
