CAPA 4 Exam Questions With Correct Answers
1. [2pt]
A metal sphere has a charge of +7.87mC (microC). What is the net charge after 6.19×1013
electrons have been placed on it?
Answer - Answer--2.03 uC
2. [2pt]
Object A is metallic and electrically neutral. It is charged by induction so that it acquires a
charge of -3.10×10-6C. Object B is identical to object A and is also electrically neutral. It is
charged by induction so that it acquires a charge of +3.10×10-6C. Calculate the difference in
mass between the charged objects.
Answer - Answer-3.53E-17 kg
3. [2pt]
In a vacuum, two particles have charges of q1 and q2, where q1 = +3.98mC (microC). They
are separated by a distance of 0.278m, and particle 1 experiences an attractive force of
3.60N. What is the magnitude of q2?
Answer - Answer-7.78E-06 C
4. [2pt]
Two tiny conducting spheres are identical and carry charges of -21.1mC (microC) and
+49.6mC (microC). They are separated by a distance of 2.60cm. What is the magnitude of
the force that each sphere experiences?
Answer - Answer-1.39E+04 N
5. [2pt]
A charge of -3.01mC (microC) is fixed at the center of a compass. Two additional charges are
fixed on the circle of the compass (radius = 0.100m). The charges on the circle are -3.97mC
(microC) at the position due north and +5.12mC (microC) at the position due east. What is
the magnitude of the net electrostatic force acting on the charge at the center?
Answer - Answer-1.75E+01 N
, 6. [3pt]
A point charge of -0.672mC (microC) is fixed to one corner of a square. An identical charge is
fixed to the diagonally opposite corner. A point charge q is fixed to each of the remaining
corners. The net force acting on either of the charges q is zero. Calculate the magnitude of q.
Answer - Answer-1.90E-06 C
7. [2pt]
At a distance r1 from a point charge, the magnitude of the electric field created by the
charge is 236N/C. At a distance r2 from the charge, the field has a magnitude of 138N/C.
Calculate the ratio r2/r1.
Answer - Answer-1.31
8. [2pt]
Two charges are placed on the x axis. One charge (q1 = +8.81mC (microC)) is at x1 = +2.60cm
and the other (q2 = -20.7mC (microC)) is at x2 = +8.79cm. Calculate the net electric field at x
= 0cm.
Answer - Answer--9.31E+07 N/C
9. [2pt]
A charge of q = +7.63mC (microC) is located in an electric field. The x and y components of
the electric field are Ex = 5.84×103N/C and Ey = 7.54×103N/C, respectively. What is the
magnitude of the force on the charge?
Answer - Answer-7.28E-02 N
10. [3pt]
An electron is released from rest at the negative plate of a parallel plate capacitor. The
charge per unit area on each plate is sigma = 1.97×10-7C/m2, and the plates are separated
by a distance of 1.63×10-2m. How fast is the electron moving just before it reaches the
positive plate?
Answer - Answer-1.13E+07 m/s
1. [2pt]
A metal sphere has a charge of +7.87mC (microC). What is the net charge after 6.19×1013
electrons have been placed on it?
Answer - Answer--2.03 uC
2. [2pt]
Object A is metallic and electrically neutral. It is charged by induction so that it acquires a
charge of -3.10×10-6C. Object B is identical to object A and is also electrically neutral. It is
charged by induction so that it acquires a charge of +3.10×10-6C. Calculate the difference in
mass between the charged objects.
Answer - Answer-3.53E-17 kg
3. [2pt]
In a vacuum, two particles have charges of q1 and q2, where q1 = +3.98mC (microC). They
are separated by a distance of 0.278m, and particle 1 experiences an attractive force of
3.60N. What is the magnitude of q2?
Answer - Answer-7.78E-06 C
4. [2pt]
Two tiny conducting spheres are identical and carry charges of -21.1mC (microC) and
+49.6mC (microC). They are separated by a distance of 2.60cm. What is the magnitude of
the force that each sphere experiences?
Answer - Answer-1.39E+04 N
5. [2pt]
A charge of -3.01mC (microC) is fixed at the center of a compass. Two additional charges are
fixed on the circle of the compass (radius = 0.100m). The charges on the circle are -3.97mC
(microC) at the position due north and +5.12mC (microC) at the position due east. What is
the magnitude of the net electrostatic force acting on the charge at the center?
Answer - Answer-1.75E+01 N
, 6. [3pt]
A point charge of -0.672mC (microC) is fixed to one corner of a square. An identical charge is
fixed to the diagonally opposite corner. A point charge q is fixed to each of the remaining
corners. The net force acting on either of the charges q is zero. Calculate the magnitude of q.
Answer - Answer-1.90E-06 C
7. [2pt]
At a distance r1 from a point charge, the magnitude of the electric field created by the
charge is 236N/C. At a distance r2 from the charge, the field has a magnitude of 138N/C.
Calculate the ratio r2/r1.
Answer - Answer-1.31
8. [2pt]
Two charges are placed on the x axis. One charge (q1 = +8.81mC (microC)) is at x1 = +2.60cm
and the other (q2 = -20.7mC (microC)) is at x2 = +8.79cm. Calculate the net electric field at x
= 0cm.
Answer - Answer--9.31E+07 N/C
9. [2pt]
A charge of q = +7.63mC (microC) is located in an electric field. The x and y components of
the electric field are Ex = 5.84×103N/C and Ey = 7.54×103N/C, respectively. What is the
magnitude of the force on the charge?
Answer - Answer-7.28E-02 N
10. [3pt]
An electron is released from rest at the negative plate of a parallel plate capacitor. The
charge per unit area on each plate is sigma = 1.97×10-7C/m2, and the plates are separated
by a distance of 1.63×10-2m. How fast is the electron moving just before it reaches the
positive plate?
Answer - Answer-1.13E+07 m/s
