1 of 3FieldsII - 1What the magnitude of the vector ˆ ˆˆ ˆ(i j) (x y)- = -?A) 1 B) 2 C) 0 D) Some other number.E) No answer, because ˆ ˆ(x y)- is not a vector.Answer: Some other number. The magnitude of the vector is 2.FieldsII - 2There are no charges inside the regions shown. Which of the following are possible electric field line configurations?A: (a) onlyB: (b) onlyC: (c) onlyD: None are possibleE: Some other answer (all, aand b only, etc.)Answer: Some other answer: (a) and (c) are possible field line diagrams.1/13/2019 PHYS1120 Dubson Fa09 ©University of Colorado(a) (b) (c)2 of 3FieldsII - 3 Consider the four electric field line patterns shown. Assume that that are no charges in the regions shown. Which, if any, of the patterns represent possible electrostatic fields.A: All are possible. B: II only C: II and III onlyD: None are possible. E: None of the above.Answer: II only.1/13/2019 PHYS1120 Dubson Fa09 ©University of ColoradoI IIIII IV3 of 3FieldsII - 4From the figure, what can you say about themagnitude of the charge on the bar Qbar,compared to the magnitude of the charge Q ofthe positive point charge?A: Q QbarB: Q QbarC: Q QbarFrom the figure, what can you say about thenet charge on the bar?A: Qbar = 0B: Qbar > 0 (that is, the bar has a net positivecharge)C: Qbar < 0 (the bar has a net negative charge)D: Not enough information in the figure to answer the question.Answers: Q Qbar, Qbar < 0FieldsII - 5 Two infinite planes are uniformly charged with the same charge per area . If one plane only were present, the field due to the one plane would be E. The field in region B has magnitude…A: zero B: E C: 2ED: depends on exact position.The field in region A has magnitude…A: zero B: E C: 2ED: depends on exact position.Answers: in region B, the field has magnitude zero. in region A, the field has magnitude 2E.1/13/2019 PHYS1120 Dubson Fa09 ©University of Colorado+ + Q Qbar ++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++ A B
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