Final_exam_Sample_test_with_solutions_old

Final_exam_Sample_test_with_solutions_old - Department of...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Department of Physics, Lehigh University Physics 21 – Introductory Physics II Spring 2010 Final Exam May 9, 2010Q ver 4 Closed Notes 8:00 AM-11:00 AM Student’s Name__Solutions______________ Recitation Section Number______________ Recitation Leader’s Name_____________________________ First, check to be sure that you have a 15-page examination, not including the cover sheet, equation sheet or the 2 pages of scrap paper. The test is a multiple-choice examination. Read all choices and choose the best response. Please answer each question by writing the letter corresponding to your choice in the answer area. Answers marked outside the answer areas will not be scored.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1. In crystals of the salt cesium chloride, cesium ions form the eight corners of a cube and a chlorine ion is at the cube's center. The edge length of the cube is 0.40 nm. The ions are each deficient by one electron (and thus each has a charge of ), and the ion has one excess electron (and thus has a charge of ). A) What is the magnitude of the net force on the ion? (a) (b) (c) (d) Answer: ____b_____ B) If one of the ions is missing, what is the magnitude of the net force? (a) (b) (c) (d) Answer: ____a_____ C) What is the direction of the force on the ion when the ion is removed? (a) Zero Net Force (b) Away from the missing ion (c) Toward the missing ion (d) None of the above Answer: ____b_____ D) Now a total of four of the ions are removed from one face of the cube, what is the magnitude of the net electric field at the center of the opposite cube face? (a) (b) 0 (c) (d) Answer: ____d_____ E) What would be the net electric flux through the face of the cube with the four missing ions? (a) (b) (c) (d) Answer: ____d_____
Background image of page 2
2. A parallel-plate capacitor has square plates with a width of 8.0 cm filled with air has capacitance C=0.56 nF. A) What is the gap size between the plates? (a) 2 mm (b) 0.1 mm (c) 0.2 mm (d) 0.02 mm Answer:____b_____ B) What is the charge on the plates if a potential difference of 125 V is applied across them? (a) 5.0x10 -10 C (b) 0.70 x 10 -7 C (c) 2.0x10 10 C (d) 0.35 x10 -6 C Answer:____b_____ C) The energy stored in the capacitor is (a) 0.42 μJ (b) 4.4 μJ (c) 84 μJ (d) 0.072 μJ Answer:____b_____ D) With the left half of the gap is filled with material of dielectric constant κ 1 = 5.0 and the right half is filled with material of dielectric constant κ 2 = 10, as shown in the figure to the right. What is the capacitance of the capacitor? (a) 9.0 nF (b) 28 nF (c) 4.2 nF (d) 3.7 nF Answer:____c_____ E) Now, if the bottom half of the gap is filled with material of dielectric constant κ 1 = 5 and the top half is filled with material of dielectric constant κ 2 = 10, as shown in the figure to the right. What is the capacitance of the capacitor? (a) 9.0 nF (b) 28 nF (c) 4.2 nF (d) 3.7 nF Answer:____d_____
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3. Four concentric spherical non-conducting surfaces (as shown) have equal amounts of charge distributed uniformly over them, with alternating signs: A of radius 1.0 cm has a total charge +150 μC B of radius 10 cm has a total charge -150 μC C of radius 20 cm has a total charge +150 μC D of radius 30 cm has a total charge -150 μC These are surface charges. There is no charge between the surfaces.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 16

Final_exam_Sample_test_with_solutions_old - Department of...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online