General Physics - Solutions to Exam 1 | PHYS 22100, Exams of Physics

Download General Physics - Solutions to Exam 1 | PHYS 22100 and more Exams Physics in PDF only on Docsity! Purdue University PHYS 221 EXAM I - 10/5/04 Please use a #2 pencil to fill in data for name, student ID #, and section on the computer sheet. Mark the correct answer for each problem on the same sheet. There will be no penalty for wrong answers. Please check to see that your exam has all 16 problems. All useful basic equations and constants are provided. Note that you will not need all of the equations and constants provided to do this exam 1 If 64 coulombs flow along a wire in 4.0 seconds, what is the average current? a, debini hon a) 64A v4) b) 32A _ AS c) 16A t= HE d) 4.0A ~ 64 = IGA 4S ra) e) None of the above 2 An aluminum nail has an excess charge of +3.2uC. How many electrons must be added to the nail to make it electrically neutral? We week to ackch Ns a) 2.0x 10% a *otal chav ge ov ~3. Oye b) 2.0 x 10% each electron. CaWYES c) 3.2x 10° So d) 3.2x 106 Aeon xo C e) 5.0x104 6, Hoe “3.AxIO Cg x10 che 1G — 1.602 X10 A power line carries 1000 A at a height of 20 m above the ground. What is the resulting magnetic field at ground level? (15 POINTS) a) 50 mT b) 0.13 mT Rm. My, 1 c) 13nT = Mo = d) 10uT AY e) 5.0 uT 4 Qe Amie “= A) (1000 A) B= 4x10 U + AO eT |) The potential differences around a loop ABCA ina circuit (starting at A and going back to A) are Vaprl0 V, Vac=6 V, and Vex. What is Vea? 16V . Nc " , Kecorcdna, ko Kay chkoff 15 Soop b) 4V ; 5) c) -4V Yoke d) -16V y ! \ | _ e) -12V Vay ¥ Voc + Vk, =O \ea = — Vee = -(\ov) - (ev) = ) -[- ev] (a) 9 An air-filled parallel plate capacitor is attached to a voltage source and charged. The voltage source is removed, and then the plates are separated to double their previous distance. What happens to the electric field between the plates when they are separated? Sn. Ye chovog a) It doubles. Yemadns constant b) It quadruples. Me £ Aeldh c) It halves. d) [tis diminished by a factor of 4. e) Itstays the same. sto Vine savne. \e) A parallel plate capacitor has a paper dielectric having dielectric strength 8.0 kV/mm and dielectric constant 3.0. The plate area is 3000 cm? and the plate separation is 0.50 mm. What is the capacitance? (15 POINTS) didecnc constr. a) 16nF va fr 20000", (42 b) 4.2nF Ce Keo A 00cen c) 5.3nF j . a d) 1.6nF a A= 0.3 0 e) 42 pF oe -1Q cc 0.4: aw c= 8) (6-354 X0 = 5m) (0.5x10>m™) [¢ =45.9 4F | 1a) 11] Two charged particles are traveling in circular orbits with the same speed in a region of uniform magnetic field that is directed into the page, as shown. The magnitude of the charge on each particle is identical, but the signs of the charges are unequal. 4 x x x . x x x x x Ssmew Be? Kg Be et AEN Ryste, 2 Gnd the vodkus 7 ron?’ SOONG aS propationol ma x x Sa x x x x x = F See od 5 ~ \ < Which one of the entries in the table below is correct? to he vrass Mass Relationship Sign of charge O, Sign of charge O; | MM, >My; a) m= Mm, aa - b) mom, = + <. / :) nS My - Y uch ¢ ‘ m “ my + Q, dn me m,> my + - 7 . e) my < my + = Asvee is porwr Fhowards Yoo Cente y of he obit , ik has to Voge negphive. Magen < , ‘ Fv Qa He Me bOvce is GA n&yg, towards Ke BD) canter of tte ovloit, iv hog to be Gos wt 12 Anegative ion is moving east near the equator where the Earth’s magnetic field is horizontal to the north. The direction of the magnetic force on the ion is N ®up @down EE. a) north. b) south. c) up. d) down. e) not meaningful since the force is zero. A He wnaciners & Force OY Wwe son VS * dous \. | A)