Home / AP Physics C Electricity and Magnetism – 2.1 Electrostatics with Conductors -MCQ Exam style question

AP Physics C Electricity and Magnetism – 2.1 Electrostatics with Conductors -MCQ Exam style question

Question

A parallel plate capacitor with air between the plates is charged and then disconnected from the source of emf. If the space between the plates is now filled with a dielectric, what happens to the
capacitance of the capacitor and the magnitude of the electric field between the plates? 

Capacitance                          Magnitude of the  Electric Field

(A) Increases                              Increases
(B) Increases                              Remains constant
(C) Increases                               Decreases
(D) Decreases                              Increases
(E) Decreases                               Decreases

Answer/Explanation

 

Question

                     

The figure above shows a cross section of two concentric spherical metal shells of radii R and 2.R, respectively. Find the capacitance.
         (A) 1/(8πεoR)
         (B) 1/(4πεoR)
         (C) 2πεoR
         (D) 4πεoR
         (E) 8πεoR

Answer/Explanation

Ans:E
Along the line joining the two charges of an electric dipole, the individual electric field vectors point in the same direction, so they add constructively. At the point equidistant from both charges, the total electric field vector has magnitude

              \(E_{+}+E_{-}=2E=2\frac{kQ}{(\frac{1}{2}d)^{2}}=\frac{8kQ}{d^{2}}\)

                                                                                           \(=\frac{8(9\times 10^{9}N.m^{2}/C^{2})(4.0\times 10^{-9}C)}{(2.0\times 10^{-2}m^{2})^{2}}\)

                                                                                               = 72 x l04  N/C
                                                                                               =7.2 x l05

Question

 Two large oppositely charged parallel plates are initially separated by a distance d. The uniform electric field between the plates has magnitude E. Next, the magnitude of the charge on each plate
 is doubled, while the separation distance d is doubled. What is the new electric field magnitude?
           (A) E
           (B) E/4
           (C) E/2
           (D) 4E
           (E) 2E

Answer/Explanation

Ans:E

 

Question

               

A parallel plate capacitor consists of identical  rectangular plates of dimensions a × b, separated by a distance c. To cut the capacitance of this  capacitor in half, which of these quantities should  be doubled?
          (A) a
          (B) b
          (C) c
          (D) ab
          (E) abc

Answer/Explanation

Ans:C

Capacitance of a parallel-plate capacitor is  εo

Question


A battery or batteries connected to two parallel plates produce the equipotential lines between the plates shown
above.
Which of the following configurations is most likely to produce these equipotential lines?

Answer/Explanation

Ans: D

The potential difference between the plates is 4V, this can be produced with two 2V batteries in

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