2010年AP电磁学简答题真题+答案+PDF下载
E&M. 1.
A charge +Q is uniformly distributed over a quarter circle of radius R, as shown above. Points A, B, and C are located as shown, with A and C located symmetrically relative to the x-axis. Express all algebraic answers in terms of the given quantities and fundamental constants.
(a) Rank the magnitude of the electric potential at points A, B, and C from greatest to least, with number 1 being greatest. If two points have the same potential, give them the same ranking.
____VA ____VB ____VC
Justify your rankings.
Point P is at the origin, as shown below, and is the center of curvature of the charge distribution.
(b) Determine an expression for the electric potential at point P due to the charge Q.
(c) A positive point charge q with mass m is placed at point P and released from rest. Derive an expression for the speed of the point charge when it is very far from the origin.
(d) On the dot representing point P below, indicate the direction of the electric field at point P due to the charge Q.
(e) Derive an expression for the magnitude of the electric field at point P.
E&M. 2.
In the circuit illustrated above, switch S is initially open and the battery has been connected for a long time.
(a) What is the steady-state current through the ammeter?
(b) Calculate the charge on the 10 mF capacitor.
(c) Calculate the energy stored in the 5.0 mF capacitor.
The switch is now closed, and the circuit comes to a new steady state.
(d) Calculate the steady-state current through the battery.
(e) Calculate the final charge on the 5.0 mF capacitor.
(f) Calculate the energy dissipated as heat in the 40 W resistor in one minute once the circuit has reached steady state.
2010年AP电磁学简答题真题余下省略！
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