9.A constant potential difference of 12 V is maintained between the terminals of

Question

9.A constant potential difference of 12 V is maintained between the terminals of 0.3 uF parallel plate capacitor with a 2 mm gap between the plates. A sheet of Plexiglas (k-3.4) is inserted between the plates, completely filling the space between the plates. How much additional charge flows onto the positive plate of the capacitor as a result of the dielectric? A. 1.1uC B.12.2uC C. 2.5uC D. 3.6uC E. 8.6 uC 10. A copper wire (density of free electrons 8.4*1028 m-3) has a diameter of 2.3mm and a length of 0.5 m. If the current density in the wire is 4.8*106 a/m2, how long does it take an electron to travel the length of the wire? A. 1.4E4 S B. 5.8E-2 S C. 3.6E-5 S D. 64 S E. 3.4E9 S

Explanation / Answer

9. initially, Q = C V = 0.3uF x 12 V

Q = 3.6 uC

now C' = k C = 3.4 x 0.3 = 1.02 uF

Q' = C' V = 12.24 uC

additional charge = Q' - Q = 8.64 uC

Ans(E)

10. Vd = J / n q

v = (4.8 x 10^6) / (8.4 x 10^28 x 1.6 x 10^-19)

v = 3.57 x 10^-4

t = L / v = (0.5) / (3.57 x 10^-4)

t = 1400 s

Related Questions

Navigate

• Browse (All)
• Browse 9
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.