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.
[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
[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
[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
[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.
[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
[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
[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
[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.
[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
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