Questions and Answers > University of California, Los Angeles - PHYSICS 5CMT1_Physics5C_S2018_solutions. Midterm #L Physics 5C Lecture 1 - David Schriver Spring Quarter - April 23,2018

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Problem I Two charges Qr:1.50 x 10-s C and Qz: -2.25 x 10-s C are aligned along the x axis at fixed positions wrrh Qr at the origin and Qz a distance 1.35 m to the right as shown in the figure. The ... charges each have a mass of 0.295 kg [10 Points] [5 Points] [5 Points] [5 Points] a) What is the total electric field due to both charges at point P located 0.450 m to the left of charge I (Qr) along the x axis, as shown in the diagram? Be sure to specify electric field as a vector that includes directionality. b) What is the force acting on charge 2 (Qz) due to charge | (Qr)? Be sure to specify force as a vector that includes directionality. c) If charge 1 were to be released from rest, what would its initial acceleration be? Be sure to specify acceleration as a vector that includes directionality. l-f rr d) e*e++Jeng+i#ib-ra&€e charge t his moved very far away (to oo) fuom charge 2, what is the magnitude of the acceleration of charge 1? Problem 2 Two charges are aligned as shown with Qr: 3.50 x 10-8 C located along the x axis 1.16 m to the left of point P and Q2: 5.25 x 10-8 C located along the y axis 1 .16 m below point P. [5 pts] [5 pts] [5 pts] [10 pts] v I P L->x 1.16 m (8.rr o f fr.rrr*B) &,t1rbq\s1u-* tr'3) t.r6 l.t6 por,tw a. ru;oivt rI OE Name Problem 2 Two charges are aligned as shown with Qr: 3.50 x 10-8 C located along the x axis 1.16 m to the left of point P and Q2: 5.25 x 10-8 C located along the y axis 1 .16 m below point P. a) What is the total electric potential at point P? b) How much energy would be required to bring a test charge that has q:4.11 x 10-3 C from very far away (at oo) to point P? c) If the test charge, initially at rest, is released from point P, what will its speed be when it is very far away (at oo)? The mass of the test charge is 0.335 kg and after the test charge is released the two charges Qr and Qzrcmain fixed in their positions. d) After the test charge is very far away at oo, the charges Qt and Qz in the positions shown in the figure are both released and allowed to move. If the masses of the two charges are equal at 0.500 kg, what is the speed of the charges when they are very far away from each other (at co)? Assume the charges move at the same speed. Problem 3 A parallel plate capacitor with a separation distance of d : 0.0335 m is charged to an 1 1.4 V potential between the plates. Each plate has a cross sectional atea A : 1.72 rr] Name Problem 3 A parallel plate capacitor with a separation distance of d : 0.0335 m is charged to an 1 1.4 V potential between the plates. Each plate has a cross sectional atea A : 1.72 rr]. a) What is the capacitance of the parallel plate capacitor and what is the magnitude of the electric field between the plates? Note that there are 2 quantities asked for. b) What is the charge per unit area on each plate and how much total charge is on each plate? Note that there are 2 quantities asked for. c) How much energy is stored in the capacitor and what is the energy density of the electric freld? Note that there are 2 qtantities asked for. d) If a dielectric with dielectric constant r: 260 is inserted between the two plates without changing the separation distance or the amount of charge on the plates, what is the new capacitance and what is the new electric field between the plates? Note that there are 2 quantities asked for. e) With the dielectric in place as described in part (d) with the same amount of charge on the plates, what is the energy density of the electric freld? Prohlem 4 A 1.25 V battery drives a current through a wire made of Nichrome that is 1.18 m long with a diameter 0.00122m. The resistivity of Nichrome is p: 1.50 x 10-6 f).m. [5 pts] a) What is the resistance of the wire? [5 pts] b) What is the current in the wire? [5 pts] c) How much power is dissipated through resistive heating in the wire? [5 pts] d) How much charge moves through the wire in 10 minutes (: 600 s)? [5 pts] e) How much energy is dissipated in 10 minutes (: 600 s)? [Show More]

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