RC Circuits

1. A large capacitor has a capacitance of 1 F. The capacitor is attached to a 10 V battery and charged to its maximum charge. What is the charge Q stored in the capacitor?

1. 0 C

2. 0.1 C

3. 1 C

4. 10 C

2. The capacitor from the previous problem is then removed from the battery and wired in series with a 10 Ohm resistor. How long does it take to discharge the capacitor to 0.2 C?

1. 50 s

2. 39 s

3. 3.9 s

4. 0.2 s

3. The capacitor is again charged, then wired in series with another resistor. What must its resistance be if we wish the capacitor to discharge to 0.2 C in 60 s?

1. 15.3 Ohms

2. 235 Ohms

3. 3000 Ohms

4. 60 Ohms

Magnetic Fields and Forces

1. An electron (charge -1.6x10^-19 C) travels at 10^5 m/s to the right. A uniform magnetic field of magnitude 1 T points out of the page. What force is felt by the electron?

1. 1.6x10^-14 N

2. 6.25x10^23 N

3. 1.6x10^-19 N

4. 10^5 N

2. An electron (charge 1.6x10^-19 C) travels at 10^5 m/s to the right. A uniform magnetic field of magnitude 1 T points out of the page. What is the direction of the magnetic force?

1. Left

2. Down

3. Up

4. Out of page

3. An electron (charge 1.6x10^-19 C) travels at 10^5m/s to the right. A uniform magnetic field of magnitude 1 T points out of the page. What will be the radius of the electron's path?

1. 1.6x10^-24 m

2. 5.7x10^-7 m

3. 1.1x10^25 m

4. 1.8x10^6 m

Electric and Magnetic Fields

1. An ion is run through a mass spectrometer with electric field 3000N/C, magnetic field 1T (in both chambers). The ion's path has a radius of 10 mm. What is its charge-to-mass ratio?

1. 300,000 C/kg

2. 30,000 C/kg

3. 3000 C/kg

4. 300 C/kg

2. A 1-m length of wire carries a current of 100 mA in a 0.8 T magnetic field. What is the maximum magnetic force that could be felt by the wire?

1. 45 mN

2. 80 N

3. 0 N

4. 80 mN

3. A 1-m length of wire carries a current of 100 mA in a 0.8 T magnetic field. What is the minimum magnetic force that could be felt by the wire?

1. 80 mN

2. 80 N

3. 45 mN

4. 0 N

Ampere's Law - Quiz

1. Two 1-m-long straight wires are parallel to each other, 10 cm apart, and carry a current of 1.5 A flowing to the left. What magnetic field will one wire feel due to the other?

1. 2.4 T

2. 18.8 micro-T

3. 0 T

4. 3.0 micro-T

2. Two 1-m-long straight wires are parallel to each other, 10 cm apart, and carry a current of 1.5 A flowing to the left. What magnetic force will one wire feel due to the other?

1. 3.6 N

2. 4.5 micro-N

3. 0 N

4. 45 micro-N

3. Two 1-m-long straight wires are parallel to each other, 10 cm apart, and carry a current of 1.5 A flowing to the left. Will the force between the wires be attractive or repulsive?

1. Attractive

2. Repulsive

3. One is attracted, but the other is repelled

4. There is no force

Flux and Faraday's Law

1. A square loop of wire with side 2cm is placed in a 0.2T magnetic field. A line perpendicular to the plane of the loop is parallel to the magnetic field. What is the magnetic flux?

1. 6.1x10^-5 Wb

2. 0 Wb

3. 5.1x10^-4 Wb

4. 8.0x10^-5 Wb

2. A square loop of wire with side 2cm is placed in a 0.2T magnetic field. A line perpendicular to the plane of the loop is 40 deg to the magnetic field. What is the magnetic flux?

1. 5.1x10^-4 Wb

2. 6.1x10^-5 Wb

3. 8.0x10^-5 Wb

4. 0 Wb

3. A square loop of wire with side 2cm is in a 0.2T magnetic field with area vector parallel to the magnetic field. The field is increased to 0.4 T in 0.2 s. What is the induced emf?

1. 1.6x10^-5 V

2. 0 V

3. 2.6x10^-4 V

4. 4.0x10^-4 V

4. The square loop from the previous problem has resistance 10 Ohms. What is the induced current in the loop?

1. 40 micro-A

2. 4 mA

3. 0 A

4. 400 micro-A

5. The loop from the previous problem lies in the plane of your screen, with the magnetic field pointing out of the screen. What direction will the current flow?

1. Out of the Page

2. Counter-Clockwise

3. Clockwise

4. There is no current

Linear Motors, Generators, and Transformers

1. The primary coil in an ideal transformer has 1000 turns of wire and an emf of 100 V. The secondary coil has an emf of 10 V. How many turns of wire does the secondary coil have?

1. 100

2. 1000

3. 10,000

4. 100,000

2. The primary coil of an ideal transformer provides 100 W of power. If the emf of the secondary coil is 10 V, how much current flows through the secondary coil?

1. 1000 A

2. 100 A

3. 1 A

4. 10 A

Here are the questions from [Inductance, RL, RC Circuits - Quiz]

1. A solenoid with cross-sectional area 1 cm^2 is 10 cm long and has 120 turns of wire. What is the inductance of the solenoid?

1. 14.4 H

2. 1.81x10^-3 H

3. 1.5x10^-7 H

4. 1.81x10^-5 H

2. An RL circuit consists of a 5 V battery connected to a 100 Ohm resistor and a 0.1 H inductor, wired in series. What is the maximum current that can flow in this circuit?

1. 5 mA

2. 50 mA

3. 0.5 mA

4. 0.05 mA

3. An RL circuit consists of a 5 V battery connected to a 100 Ohm resistor and a 0.1 H inductor, wired in series. What is the time constant of this circuit?

1. 1 ms

2. 10 s

3. 316 ms

4. 1000 s

4. An RL circuit consists of a 5V battery connected to a 100 Ohm resistor and a 0.1H inductor wired in series. What is the current in the circuit 0.5ms after the battery is connected?

1. 50 mA

2. 80.3 mA

3. -32.4 mA

4. 19.7 mA

5. An LC circuit consists of a 5 mF capacitor wired in series with a 0.2 H inductor. What is the frequency (in Hz) of this circuit?

1. 0.2 Hz

2. 5.0 Hz

3. 31.6 mHz

4. 31.6 Hz

Here are the questions from [Reactance, Impedance, RLC Circuits - Quiz]

1. A 100 VRMS AC emf source with frequency 50 Hz is connected to a 0.5 H inductor and 20 mF capacitor wired in series. What is the inductive reactance of the circuit?

1. 8 Ohm

2. 157 Ohm

3. 25 Ohm

4. 50 Ohm

2. A 100 VRMS AC emf source with frequency 50 Hz is connected to a 0.5 H inductor and 20 mF capacitor wired in series. What is the capacitive reactance of the circuit?

1. 8 Ohm

2. 50 Ohm

3. 159 m-Ohm

4. 157 Ohm

3. A 100 VRMS AC emf source with frequency 50 Hz is connected to a 0.5 H inductor and 20 mF capacitor wired in series. What is the impedance of the circuit?

1. 22,200 Ohm

2. 0 Ohm

3. 165 Ohm

4. 157 Ohm

Intro to Light

1. Blue light has a wavelength of 450 nm in a vacuum. What is its frequency?

1. 6.67x10^14 Hz

2. 6.67x10^5 Hz

3. 1.5x10^-15 Hz

4. 4.19x10^15 Hz