Phy102&amp;08-II-final

# Phy102&amp;08-II-final - 1 1 The point charge Q below...

This preview shows pages 1–4. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 1. The point charge Q below is stationary. The electric potential energy U of the system is- 37 nJ if point charge q is at A . As q moves from A to B , the work done on q (by the electric field of Q ) is +23 nJ. What is U when q is at B ? [2] Q × × A B q Δ U = U B- U A =- (Work done by vector E Q ) =- 23 nJ U B = U A + Δ U = (- 37 nJ) + (- 23 nJ) =- 60 nJ 2. When the capacitors below are fully charged, the 6.00 μ F-capacitor has a charge of 36.0 μ C. What is the charge of 4.00 μ F-capacitor? [2] 3.00 μ F 6.00 μ F 4.00 μ F Q 3 . 00 μ F = 3 . 00 μ F 6 . 00 μ F Q 6 . 00 μ F = 18 . μ C Q 4 . 00 μ F = Q 3 . 00 μ F + Q 6 . 00 μ F = (18 . μ C) + (36 . μ C) = 54 . μ C 2 3. In the diagram below, q = 0 . 10 nC and d = 3 . 0 cm. Find the x-component E x of the net electric field at the point with coordinates (- 4.0 cm, +4.0 cm). [4] r + q = √ 17 . 0 cm r- q = √ 65 . 0 cm cos θ + q = 1 . √ 17 . cos θ- q = 7 . √ 65 . x y- q + q d d × θ + q θ- q vector E + q vector E- q E x =-| vector E + q | cos θ + q + | vector E- q | cos θ- q =- 8 . 2 N/C 4. A point charge q = 2 . 40 nC is at the center of a spherical conducting shell (inner radius of 1.00 cm, outer radius of 1.20 cm). The electric field 4.00 cm from the center of the shell has a magnitude of 5.00 kV/m and points radially inward. Find the surface charge density on the outer surface of the shell. (Justify your choice of sign.) [3] q | Q outside | = 4 πǫ (4 . 00 cm) 2 | vector E | = 8 . 89 × 10- 10 C | σ | = | Q outside | 4 π (1 . 20 cm) 2 = 4 . 91 × 10- 7 C/m 2 σ < 0 : vector E inward 3 5. Three long straight parallel wires (seen end-on below) carry currents out of the page; a = 2 . 50 cm. Find the magnitude of the50 cm....
View Full Document

{[ snackBarMessage ]}

### Page1 / 7

Phy102&amp;08-II-final - 1 1 The point charge Q below...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online