Important! Physics 2220 Spring 2014 Paolo Gondolo PLEASE FILL IN THE INFORMATION BELOW. Name (printed): Name (signed): Student ID Number

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1 Physics 2220 Spring 2014 Paolo Gondolo EXAM 3 PLEASE FILL IN THE INFORMATION BELOW Name (printed): Name (signed): Student ID Number U Discussion Instructor: Anthony KC Matt Paul Peter Important! You are not required to answer all questions in this exam. You will receive points toward your exam points for every question correctly answered. Partial credit is available, however a minimum amount of work and explanation must be shown to receive any credit (for example, a mere list of equations with no explanation of their connection to the problem will not receive credit).

2 Physics 2220 Spring 2014 Paolo Gondolo Data: Use these constants (where it states, for example, 1 ft, the 1 is exact for significant figure purposes). 1 ft = 12 in (exact) 1 m = 3.28 ft 1 mile = 5280 ft (exact) 1 hour = 3600 sec = 60 min (exact) 1 day = 24 hr (exact) g earth = 9.80 m/s 2 = 32.2 ft/s 2 g moon = 1.67 m/s 2 = 5.48 ft/s 2 1 year = days 1 kg = slug 1 N = pound 1 horsepower = 550 ft pounds/s (exact) M earth = kg R earth = km M sun = kg R sun = m M moon = kg R moon = km G = N m 2 /kg 2 k = N m 2 /C 2 ε o = C 2 /(N m 2 ) e electron charge = C m electron = kg μ o = 4π 10-7 T m/a (exact) N(Avogadro's No.) = atoms/gm mole = atoms/kg mole 1 Tesla = 10,000 gauss (exact) ρ(h 2 O) = 1000 kg/m 3 cos(a ± b) = cos a cos b a sin b sin(a ± b) = sin a cos b ± sin b m proton = kg h = J π = 3.14 c = m/s 3 1 x x a dx x a 3 dx x x a 3 a 2 x 2 a 2 ax 1 e dx e a ax xdx 1 3/ 2 x a x a xdx a x a x dx n x x a x a dx 1 a x a n x x a a x xdx x a x a dx 1x 1x sin, or cos a x a a dx 1 n a bx a bx b dx 1 2 a bx ba bx

3 Physics 2220 Fall 2009 Spring 2014 Paolo Gondolo Name: Unid: Discussion TA: Exam 3 1 Show all work!! Report all numbers to three (3) significant figures. A 2.0-cm-tall candle flame is 2.0 m from a wall. You happen to have a lens with a focal length of 32 cm, and you know you can use it to form a well-focused image of the candle flame on the wall. (c) [10 pts.] Is the lens you have converging or diverging? Explain. [10 pts.] How far from the candle flame should you put the lens? List all locations along the perpendicular line from candle to wall. [10 pts.] For each location in part, what are the height and orientation of the image (upright or inverted)?

4 Physics 2220 Fall 2009 Spring 2014 Paolo Gondolo Name: Unid: Discussion TA: Exam 3 2 Show all work!! Report all numbers to three (3) significant figures. Shown from above in the figure is one corner of a rectangular box filled with water (index of refraction 1.33). A laser beam starts 10 cm from side A of the container and enters the water at position x. You can ignore the thin walls of the container. [10 pts.] Find the angle of reflection and refraction of the laser beam on side B if x = 25 cm. [10 pts.] Repeat part for x = 15 cm.

5 Physics Fall 2009 Spring 2014 Paolo Gondolo Name: Unid: Discussion TA: Exam 3 3 Show all work!! Report all numbers to three (3) significant figures. A double-slit experiment produces interference fringes on a distant screen. How does the linear separation beween the bright maxima on the screen change when: (c) (d) [10 pts.] The wavelength of the light doubles? [10 pts.] The separation between the slits doubles? [10 pts.] The distance between the slits and the screen doubles? [10 pts.] The intensity of the light doubles?

6 Physics Fall 2009 Spring 2014 Paolo Gondolo Name: Unid: Discussion TA: Exam 3 4 Show all work!! Report all numbers to three (3) significant figures. You are using your cell phone, which receives an 800 MHz signal, and between you and the cell phone tower, which is on your north side, there are two massive, microwave-absorbing buildings that have only a 15 m space between them (see figure). You walk due west along a straight line 90 m south of the buildings. [10 pts.] How far west from the central maximum is the first minimum of the cell phone signal? [10 pts.] How much farther west is the next maximum?

7 Physics Fall 2009 Spring 2014 Paolo Gondolo Name: Unid: Discussion TA: Exam 3 5 Show all work!! Report all numbers to three (3) significant figures. A 75-W light bulb radiates uniformly in all directions, and 9 percent of this energy is emitted as electromagnetic radiation in the visible light range. At a distance of 130 cm from the bulb, (c) [10 pts.] What is the intensity of the visible light from the bulb? [10 pts.] What is the electromagnetic energy density of the visible light? [10 pts.] What are the peak values of the corresponding electric and magnetic fields?

8 !'h,,.,,.:::20 Sprin:,!. 201-t Paolo Condolo Nmne: ----~:tj\~~~~~~m~) Unid: ~ Discussion T A: Exam3 1 Sllow all work!! Report all numbers to three (3) significant figures. A 2.0-cm-tall candle flmne is 2.0 m from a wall. You happen to have a lens with a focal length of 32 em, and you know you can use it to fonn a well-focused image of the candle flame on the wall. I (c) [1 0 pts.] Is the lens you have converging or diverging? Explain. [10 pts.] Ho~ far from the candle flame should you put the lens? List all locations along the perpendicular line from candle to wall. [10 pts.] For each location in part, what are the height and orientation of the image {upright or inverted)? Candle ' f + t ~J J~2... f="jl CWI -::- 1 2 WI I --~ -:: - - I I I I P+ t J ft ('! f => --;;;l::j => = ]. -~ ft '!= ol-f ~J-f P(J-f)=J.f -f 7 +fj =-~J f :: C f: I. 6,..., -- f, ~p - 2 ~ J 4 -.,. (' 1Z )( 1.) 2 G M I o.+ ~I \ f ;:: (},4- W1: I _-P-f'J, ::. n 1 - p- "r ; l- J c ~ 1 Pnve...r+J.

9 I '!1\ '",, 2 ~ 20 Sprin~ 20 1-t Paolo (. ondolo Name: fe-}if Unid: ---' Discussion TA: Exam3 2 Sllcny all world! Reoort all numbers to three (3) significant figures. Shown from above in the figure is one corner of a rectangular box filled with water (index of refraction 1.33). A laser beam starts 10 em from side A of the container and enters the water at position x. You can ignore the thin walls of the container. {10 pts.} Find the angle of reflection and refraction ofthe laser beam on side B ifx = 25 em. {10 pts.] Repeat part for x = 15 em. (~) -X s~e.tl' $,e.ll : -. Anale. ::: ItS. 1o ~ 1> :t frl. 1)1.M 'f <f' 'f ~ > of refract tot'z. : 1>~,A = ~ rc:s,.n ( ~ 1'1\''"- 'f) r A "ale. fj f reflec.tt'o ""- : An~le.

10 .._ "'0 1-4 Paolo (. ondolo I 'It''"' '20 1'~" 111!.!- Name: _«R~ II,-!. ~N~--~------l.,-- Unid: _; Discussion TA: Exam3 3 Slaow an work!! Report all numbers to three (3) significant figures. A double-slit experiment produces interference fringes on a distant screen. How does the linear separation beween the bright maxima on the screen change when: ~ (c) (d) [10 pts.] The wavelength ofthe light d~ubles? [J 0 pts.] The separation between the.shts doubles?? [10 pts.] The distance between the shts and the screen doubles. [10 pts.] The intensity of the light doubles? ~ lf,l4.){1""'4- t:~t-n.--l j.,iau,~w-a- Y 14 '/!.. ~-, (- 1., T~--- da,. /~" e~ 0, d ~,t..t~~ :::: Wt.A L -n. ro e.. 5.;f?'e..._,f ott"- 1M-<J::!.- 146X L... a_ /s rf' 'v e<-.. h y : y.. "" L ::J -t."' $.._ ((o> s ~<-...;d/.;k..c! 1 ~ st._).rf ~" ~4 (bl If d.''= z.d L/k~ -;;~~o~.' :::) ~ do~h fes ha-lv~> (cl> I.f.J d 9.,J; fes ~ Af~ A.t s,~.,.~~ eft;,~ U/DIV e-le.(ji<.. ~).., s )if ~ep<~j""a-1-i"'-~ d _, CA.~ disftjf(.c,e- ~ c:;-cr6 ~-~ L, dr-t:- et-!1 ~~~4YU.-tt-

11 1'1",,, '~-'fl Sprmg 2014 Paolo Condolo Nwme: ----+J?~a~-~)1~ Unid: Discussion TA: ~ Exam3 4 SIMny all work!! Reoort all numbers to three (3) significant figures. You are using your cell phone, which receives an 800 MHz signal, and between you and the cell phone tower, which is on your north side, there are two massive, microwave-absorbing buildings that have only a 15m space between them (see figure). You walk due west along lit straight line 90 m south of the buildings. [10 pts.] How far west from the central maximum is the first minimum of the cell phone signal? [10 pts.] How much farther west is the next maximum? - Gl 15m s 0 0\ ~

12 Name:.:...;1'1\.:...::::Q.~rtf..J....::... Unid: Discussion TA: ~ r ) Exam3 5 Sllcnv all work!! Report all numbers to three (3) significant figures. A 75-W light bulb radiates unifonnly in all directions, and 9 percent of this energy is emitted as electromagnetic radiation in the visible light" range. At a distance of 130 em from the bulb, (c) [10 pts.] What is the intensity ofthe visible light from the bulb? [10 pts.] What is the electromagnetic energy density ofthe visible light? [10 pts.] What are the peak values ofthe corresponding electric and magnetic fields? c)