# CCCHSTC Current and Resistance Test Two Solutions Worksheet

Description

Name:
Physics 236 Test Two
50 V
+

1 mm
Volts
Figure 1
1) (20 pts.) Two plates 1 m2 each have a 1 mm gap between them. What is the capacitance?
The capacitor is fully charge to 50 V then remove from the power supply, a dielectric with 𝜅 =
2.5 is placed between the plates. What is the new voltage across the capacitor with the
dielectric, remember charge q is still the same, but electric field will change?
EMF
Figure 2
2) (20 pts.) An RC circuit has a 5.5 kΩ resistor and a 8.0 µF capacitor in series, how long will it
take for the fully discharged capacitor to be charged to 95% once the switch is closed? _______
How long would it if a second 8.0 µF capacitor is added in series? _______
3) (10 pts) A particle with a charge of +9.0 µC is going from left to right at 5.5×105 m/s.
There is a 2 T field going into the paper. Using 𝐹 = 𝑞𝑣𝐵𝑠𝑖𝑛𝜃 find the magnitude and
direction of the force.
4) (10 pts.) If the charge in problem 3 has a mass of 3.0×10-7 kg, what is the radius of curvature
for the particle’s motion?
5) (10 pts.) Magnetic torque is:
𝜏 = 𝐵𝐼𝐴𝑠𝑖𝑛𝜃
A loop of wire has a radius of 3cm and is 30 degrees to a 2 T field with 1.5 A current. What is the
torque (state units)? ________________
+

+
35 k ohm
12 V
15 k ohm
6V

25 k ohm
6) (20 pts.) Find the current through each of the three resistors.
7) (10 pts.) Aluminum has a resistivity of 2.8 x 10-8 ohm-meter. How would you shape 0.001 m3
of Aluminum so it would have 1 ohm of resistance? (more than one correct answer)
Name:
Physics 236 Test Two
50 V
+

1 mm
Volts
Figure 1
1) (20 pts.) Two plates 1 m2 each have a 1 mm gap between them. What is the capacitance?
The capacitor is fully charge to 50 V then remove from the power supply, a dielectric with 𝜅 =
2.5 is placed between the plates. What is the new voltage across the capacitor with the
dielectric, remember charge q is still the same, but electric field will change?
EMF
Figure 2
2) (20 pts.) An RC circuit has a 5.5 kΩ resistor and a 8.0 µF capacitor in series, how long will it
take for the fully discharged capacitor to be charged to 95% once the switch is closed? _______
How long would it if a second 8.0 µF capacitor is added in series? _______
3) (10 pts) A particle with a charge of +9.0 µC is going from left to right at 5.5×105 m/s.
There is a 2 T field going into the paper. Using 𝐹 = 𝑞𝑣𝐵𝑠𝑖𝑛𝜃 find the magnitude and
direction of the force.
4) (10 pts.) If the charge in problem 3 has a mass of 3.0×10-7 kg, what is the radius of curvature
for the particle’s motion?
5) (10 pts.) Magnetic torque is:
𝜏 = 𝐵𝐼𝐴𝑠𝑖𝑛𝜃
A loop of wire has a radius of 3cm and is 30 degrees to a 2 T field with 1.5 A current. What is the
torque (state units)? ________________
+

+
35 k ohm
12 V
15 k ohm
6V

25 k ohm
6) (20 pts.) Find the current through each of the three resistors.
7) (10 pts.) Aluminum has a resistivity of 2.8 x 10-8 ohm-meter. How would you shape 0.001 m3
of Aluminum so it would have 1 ohm of resistance? (more than one correct answer)