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Two point charges, one q and the other q, form a dipole separated by a distance d. A third charge Q is placed midway between these two charges. If the distance between q and q is then doubled with the Q staying midway between the other two, what happens to the force on Q?
 a. It halves. b. It reduces by a factor of 8.
  c. It stays the same. d. It quarters.

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[Ques. 2] An electromagnetic wave with a peak magnetic field component of 3.20  107 T carries what average power per unit area? (0 = 4  107 Tm/A, 0 = 8.85  1012 C2/Nm2 and c = 3.00  108 m/s)
 a. 38.4 W/m2
  b. 24.4 W/m2
  c. 12.2 W/m2
  d. 3.82 W/m2
  e. 7.64 W/m2

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[Ques. 3] Q1 has 50 electric field lines radiating outward and Q2 has 250 field lines converging inward. What is the ratio Q1/Q2?
 a. 5
  b. 5
  c. 1/5
  d. 1/5
  e. 0

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[Ques. 4] An electromagnetic wave with a peak magnetic field component of 1.59  107 T has an associated peak electric field component of what value? (0 = 4  107 Tm/A, 0 = 8.85  1012 C2/Nm2 and c = 3.00  108 m/s)
 a. 2.10E2 N/C
  b. 5.30E9 N/C
  c. 4.77E+1 N/C
  d. 1.89E+8 N/C
  e. 5.99E6 N/C

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[Ques. 5] Charge A has 10 electric field lines coming out, Charge B has 20 lines coming out, and Charge C has 30 lines coming in. Which pair of these charges will have the largest force between them if placed one cm apart?
 a. A and B
  b. B and C
  c. C and A
  d. More information is needed.

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[Ques. 6] An electromagnetic wave with a peak electric field component of 1.11  102 N/C has what associated peak magnetic field value? (0 = 8.85  1012 C2/Nm2, 0 = 4  107 Tm/A and c = 3.00  108 m/s)
 a. 3.33E+10 T
  b. 2.70E+6 T
  c. 3.70E7 T
  d. 4.65E13 T
  e. 7.34E+3 T

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[Ques. 7] Two point charges, separated by 1.7 cm, have charge values of +2.0 and 4.0 C, respectively. Suppose we determine that 50 field lines radiate out from the +2.0-C charge. If so, what might be inferred about the 4.0-C charge with respect to field lines?
 a. 25 radiate out
  b. 100 radiate out
  c. 100 radiate in
  d. 50 radiate in
  e. 50 radiate out

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[Ques. 8] A 6.0-J pulse of light from a laser has what momentum?
 a. Light does not have momentum because it doesn't have mass.
  b. 3.0  109 kgm/s
  c. 6.7  109 kgm/s
  d. 2.0  108 kgm/s

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[Ques. 9] The number of electric field lines passing through a unit cross-sectional area is indicative of
 a. field direction.
  b. charge density.
  c. field strength.
  d. charge motion.

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[Ques. 10] Which condition of motion must be met with regard to a charged particle if it is in the process of emitting electromagnetic radiation?
 a. moves at constant velocity
  b. accelerates
  c. moves at the speed of light
  d. moves parallel to a uniform magnetic field

1)  d

2)  c

3)  d

4)  c

5)  b

6)  c

7)  c

8)  d

9)  c

10)  b

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