exam 2 new

1. 1The magnitude J of the current density in a certain wire with a circular cross section of
   radius R = 2.00 mm is given by J = (3.00 × 10^8)r^2, with J in amperes per square meter
   and radial distance r in meters. What is the current through the wire?
   

   1. A1.02 × 10^−2 A
   2. B7.54 × 10^−3 A
   3. C4.40 A
   4. D1.70 × 10^−5 A
   5. E6.12 × 10^−6 A
2. 2Consider the assembly of capacitors shown here. Let C1 = C2 = C3 = C4 = 20 mF.
   What is the equivalent capacitance of this circuit?

   

   1. A40 mF
   2. B80 mF
   3. C30 mF
   4. D20 mF
   5. E15 mF
3. 3Wire 1 has a resistance R1. Wire 2 is made of the same material, is three times as long
   and has twice the diameter. What is the ratio R2/R1?
   

   1. A1/1
   2. B3/2
   3. C5/2
   4. D3/4
   5. E2/3
4. 4An air-filled parallel-plate capacitor has a capacitance of 1.3 pF. The separation of the
   plates is doubled, and wax is inserted between them. The new capacitance is 2.6 pF.
   Find the dielectric constant of the wax.

   1. A7.50
   2. B5.75
   3. C2.50
   4. D4.00
   5. E6.80
5. 5How does the capacitance of two identical capacitors connected in series compare to that
   of one of the capacitors?

   1. AThe two capacitors connected in series have a larger capacitance
   2. BThe two capacitors connected in series has the same capacitance.
   3. CThe two capacitors connected in series have a smaller capacitance.
6. 6A portion of a circuit is shown, with the values of the currents given for some branches.
   What is the direction and value of the current i?

   

   1. A↑, 4 A
   2. B↑, 6 A
   3. C↓, 4 A
   4. D↓, 6 A
   5. E. ↓, 2 A
7. 7During the 4.0 min that a 5.0 A current flows in a wire, how many electrons pass through
   any cross section along the wire?

   1. A9.7 × 10^20
   2. B4.2 × 10^19
   3. C5.7 × 10^19
   4. D3.1 × 10^18
   5. E7.5 × 10^21
8. 8Four 18.0 Ω resistors are connected in parallel across a 25.0 V ideal battery. What is the
   current through the battery?

   1. A1.39 A
   2. B0.347 A
   3. C5.56 A
   4. D3.47 A
   5. E18.0 A
9. 9An uncharged capacitor with C = 31.4 µF, a resistor with R = 24.3 kΩ, and a battery
   with V = 25.7 V are connected in series. What is the charge q on the capacitor ata time
   equal to three time constants (t = 3τ ), after the switch is closed?

   1. A1.50 × 10^−6 C
   2. B3.31 × 10^−4 C
   3. C2.73 × 10^−6 C
   4. D7.67 × 10^−4 C
   5. E8.97 × 10^−4 C
10. 10What is the resistivity of a wire 1.0 mm diameter, 2.0 m length, and 50 mΩ resistance?

    1. A2.0 × 10^−8 Ω.m
    2. B1.2 × 10^−8 Ω.m
    3. C4.5 × 10^−8 Ω.m
    4. D8.9 × 10^−8 Ω.m
    5. E3.7 × 10^−8 Ω.m

11. 11Thermal energy is produced in a resistor at a rate of 100 W when the current is 3.00 A.
    What is the resistance?

    1. A1.00 Ω
    2. B0.0300 Ω
    3. C11.1 Ω
    4. D15.0 Ω
    5. E. 5.02 Ω
12. 12The figure shows a parallel-plate capacitor with plate area A = 5.56 cm2 and plate
    separation d = 5.56 mm. The left half of the gap is filled with material of dielectric
    constant κ1 = 7.00; the right half is filled with material of dielectric constant κ2 = 12.0.
    What is the capacitance?
    

    

    1. A1.48 × 10^−12 F
    2. B5.56 × 10^−12 F
    3. C7.12 × 10^−12 F
    4. D8.41 × 10^2 F
    5. E3.12 × 10^−12 F
13. 13Given a 48.0 V battery and 24.0 Ω and 96.0 Ω resistors, find the current when connected
    in series.

    1. A7.00 A
    2. B2.50 A
    3. C0.500
    4. D2.00 A
    5. E0.400 A
14. 14Your electricity bill gives your consumption in units of kilowatt-hour (kW · h). Does this
    unit represent the amount of

    1. Acharge
    2. Bcurrent
    3. Cvoltage
    4. Dpower
    5. Eenergy
15. 15Find the charge stored when 5.50 V is applied to an 8.00 pF capacitor?

    1. A4.40 × 10^−11 C
    2. B1.45 × 10^−12 C
    3. C6.88 × 10^−11 C
    4. D3.22 × 10^−11 C
    5. E2.71 × 10^−11 C

Descripción

Test sobre exam 2 new, creado por hank fournier el 31/07/2018.

Autor

hank fournier

Idioma

English

Visitas

0

Valoración

Aún sin valoraciones

Valora este test

Valora este test

Más sobre Capacitors and Capacitance