Unit 7: Waves and Sound

Transcription

1 Phyic Unit 7: Wave and Sound. Know meaning of reflect, interference, beat, contructive, detructive, frequency, uperpoition, wavelength, tanding wave, fundamental frequency, harmonic (i.e. t harmonic, 2nd harmonic, overtone (i.e. t overtone, 2nd overtone, reonate. 2. Be able to claify wave by type (longitudinal, tranvere, or both. 3. Know the value of the threhold of hearing. 4. Know how frequency and pitch are related. 5. Know how decibel and loudne are related. 6. Know what affect the peed of a wave (v = fλ and all the peed formula 7. Know ome drawing to repreent tanding wave in open and cloed tube. 8. How are tanding wave produced? 9. How are beat produced? 0. What happen when two wave pule traveling oppoite direction meet?. Do wave: move energy? Move matter from place to place? Have a traveling diturbance? 2. What i the λ for a wave with a peed of 0 m/ and a period of 40? 3. A wave ha a frequency of 30 Hz and a peed of 60 m/. What i the wavelength of the wave? 4. In the following graph, what i the amplitude, wavelength and frequency of wave A i it peed i 5 cm/? 5. A ubmarine end out a onar ping. The return echo i heard 20 later. If the peed of ound i 522 m/, how far away i the reflecting urface? 6. The intenity of a pherical wave 5 m from the ource i 200 W/m 2. What i the intenity at a point 0 m away from the ource? 7. The decibel level of rock concert i 20 db relative to the threhold of hearing. Determine the ound intenity produced by the concert. 8. A car moving at contant peed pae a boy playing a concert A (440 Hz on an intrument. After the car ha paed the driver hear the note a a concert E (330 Hz. How fat wa the car going (peed of ound = 343 m/? 9. A car moving at 50 m/ approache a train whitling. The train i moving toward the car at a peed of 0 m/. The whitle i et at 200 Hz. What i the frequency heard by the driver of the car? 20. A guitar tring produce 0 beat/ when ounded with a 440 Hz tuning fork and 5 beat/ when ounded with a 445 Hz tuning fork. What i vibrational frequency of the tring? 2. A 2-m long tring vibrate in 4 egment. The wave peed i 40 m/. What i the frequency of vibration? 22. A 2-m long tring vibrate in 4 egment. The wave peed i 40 m/. What i the lowet poible frequency for tanding wave on thi tring? 23. Determine the hortet length of pipe, open at both end, which will reonate at 440 Hz. The peed of ound i 343 m/. 24. A pring i ued on a jumping toy. The bottom of the toy ha a uction cup that keep the pring compreed. If the uction cup upplie 5 N of force to keep the pring compreed 3 cm, what i the pring contant? 25. The -tring on a certain guitar i under 00 N of tenion. If the frequency i 200 Hz and the wavelength i 2.0 m, find the linear denity of the tring.

2 . a. Ye b. No c. Ye 2. v = 0 m, 40 v = λ T 0 m = λ 40 λ = 0 m (40 = 400 m 3. f = 30 Hz, v = 60 m v = fλ 60 m = 30 Hz λ λ = 2 m 4. A = 4 cm, λ = 6 cm, f = Hz v = fλ = f 6 cm = 5 cm 5. t = 20 (t = 0 for one way, v = 522 m x = vt x = 522 m (0 = 5220 m 6. 5 m, I = 200 W m 2 0 m, I =? I = P, A = 4πr2 A 200 W m 2 = P I = P = W 4π(5 m W = 50 W/m2 4π(0 m 2 7. β = 20 db, I 0 = 0 2 W m 2 β = (0 db log ( I I 0 I 20 db = (0dB log ( 0 2 W m 2 I 2 = log ( 0 2 W m 2 I 0 2 = 0 2 W m 2 I =. 0 W/m 2 8. f = 440 Hz, f 0 = 330 Hz, v = 343 m f 0 = f ( v w ± v o v w v 330 Hz = 440 Hz ( 343 m v o 343 m = 343 m v o 343 m m = 343 m v o v 0 = m 9. v 0 = 50 m, v = 0 m, f = 200 Hz f 0 = f ( v w ± v o v w v f 0 = 200 Hz ( 343 m + 50 m 343 m 0 m = 236 Hz 20. f g 440 Hz = 0 Hz f g = 450 Hz or 430 Hz f g 445 Hz = 5 Hz f g = 450 Hz or 440 Hz 2. L = 2 m, n = 4, v = 40 m, f =? f n = n ( v 2L f 4 = 4 ( 40 m = 40 Hz 2(2 m 22. L = 2 m, n =, v = 40 m f n = n ( v 2L f = ( 40 m = 0 Hz 2(2 m 23. f = 440 Hz, n =, v = 343 m f = n ( v 2L 440 Hz = ( 343 m 2L 440 Hz = 7.5 m L L = 7.5m = m 440 Hz 24. F = 5 N, x = 0.03 m F = kx 5 N = k( 0.03 m 500 N m = k 25. F = 00 N, f = 200 Hz, λ = 2.0 m v = fλ v = (200 Hz(2.0 m = 400 m v = F m L 400 m m2 2 m L = N = 00 m L 00 N = m L 00 N = m2 0 4 kg/m 2

3 Phyic Unit 8: Electric Force and Electric Field. What i the charge of an electron? 2. What i the value of k? 3. What are ome combination of charge that attract? Repel? 4. Know the tep to charge by contact and by induction. 5. Definition: electric potential difference, electric potential energy, capacitor, dielectric, equipotential line, electric field, electric field line, conductor, inulator 6. I electric force conervative? 7. A piece of wire ha a charge of C. How many extra electron doe it have? 8. At what eparation will two charge, each of magnitude 0.0 μc, exert a force of 5 N on each other? 9. A -0.0-µC charge i located 0.50 m to the right of a +5.0-µC charge. What i the magnitude and direction of the electrotatic force on the poitive charge? 0. Know about the electric field in a parallel plate capacitor.. How i the pacing of the electric field line related to the trength? 2. How i the number of electric field line related to the ize of the charge? 3. Where are the exce charge on a conductor located? 4. What i the magnitude and direction of the electric force on a +5 μc charge at a point where the electric field i 5000 N/C and i directed on the x axi? 5. The electric potential at a certain point in pace i 6 V. What i the electric potential energy of a -4 C charge placed at that point in pace? 6. If a 2-C charge i located at the origin and a -3-C charge i located at x = 2 m, where i the electric potential zero? 7. If the work required to move a C charge from point A to point B i +00 J, what i the potential difference between the two point? What i the difference in potential energie of A and B? 8. Given a picture of a equipotential line, be able to find area of greatet electric potential energy and electric field trength. 9. A capacitor ha a very large capacitance of 00 F. The capacitor i charged by placing a potential difference of 3 V between it plate. How much energy i tored in the capacitor?

4 C Nm2 C 2 3. Attract: +,-; +,0; -,0; Repel: +, +; -, - 4. See textbook or note C = C 04 electron 8. F = k q q 2 r 2 5 N = ( Nm2 C 2 (0 0 6 C(0 0 6 C r 2 r 2 = ( Nm2 (0 0 6 C(0 0 6 C 2 C 5 N r 2 = m 2 r = m 9. F = k q q 2 r 2 F = ( Nm2 C 2 ( C(5 0 6 C (0.5 m 2 F = N to the right 0. Contant, etc.. Wider pace, le field 2. More line, more charge 3. On urface 4. E = F q 5000 N C = F C F = N N in the -x direction 5. V = EPE q 0 6 V = EPE 4 C EPE = 24 J 6. V = kq r k(2 C k( 3 C + x 2 x = 0 (2 xk(2 C xk( 3 C + x(2 x x(2 x = 0 (2 x(2 C + x( 3 C = 0 4 C (2 Cx (3 Cx = 0 4 C = (5 Cx x = 0. 8 m 7. V B V A = EPE B q 0 V B V A = W AB V B V A = q 0 00 J 0.25 C EPE A q 0 = 400 V = W AB q 0 W AB = W BA = 00 J 8. EPE: electron ha highet EPE at lowet V and proton ha highet EPE at highet V E-field: highet at place where equipotential line are cloet together 9. E cap = CV2 2 (00 F(3 V2 E cap = = 450 J 2

5 Phyic Unit 9: Electric Circuit. What i emf, kwh, rm, current, reitance, reitivity, and potential difference? 2. How do you ue ammeter and voltmeter? 3. Know what factor your body enitivity to electricity? 4. Ue Kirchhoff Law to olve problem. 5. A 2-A current flow through a circuit. How much charge pae a point during minute? 6. A flahlight bulb i connected to a 3.0 V battery and a current of.020a flow. What i the reitance of the bulb filament? 7. The reitivity of a metal i 3x0-8 m. The radiu of the wire i 2 mm. If the length of the wire i 3 m, what i the reitance of the wire? 8. A 2-A current flow through a circuit with a reitance of 5. How much energy i diipated in 3? 9. A 2-A current flow through a circuit that conit of a reitor and an ideal battery. If the battery upplie 400 W, how large i the reitor? 0. An AC voltage ha a rm value of Determine the peak value of the voltage?. Three reitor, 2-, 3-, 4-, are connected in erie. What i the equivalent reitance of the erie? 2. Two 0- and four 30- light bulb are connected in erie with a 9 V battery. What i the current that pae through each bulb? 3. Three reitor, 2-, 3-, 4-, are connected in parallel. What i the equivalent reitance of the combination? 4. What i the equivalent reitance of figure 0 Figure A non-ideal battery ha a 2.0 V emf and internal reitance of 4. Determine the terminal voltage of the battery when 2 A i drawn. 6. An uncharged 0 F capacitor and a reitor are connected in erie to a 9 V battery and an open witch to form a imple RC circuit. The witch i cloed at t = 0. The time contant of the circuit i 30. A How big i the reitor and Bwhat i the maximum charge on the capacitor?

6 5. I = q t 2A = q 60 q = 20 C 6. V = IR 3 V = (0.02 AR R = 50 Ω 7. R = ρ ( L A A = πr 2 = π(0.002 m 2 = m 2 R = (3 0 8 Ωm ( 0 3 Ω 8. P = I 2 R P = (2 A 2 (5 Ω = 20 W P = W t 20 W = W 3 W = 60 J 9. P = I 2 R 400 W = (2 A 2 R R = 00 Ω 0. V rm = V 2 3 m m 5.66 V = V 2 V = 8. 0 V. R S = R + R 2 + R 3 R S = 2 Ω + 3 Ω + 4 Ω = 9 Ω 2. R S = R + R 2 + R 3 + R 4 + R 5 + R 6 R S = 2 (0 Ω + 4 (30 Ω = 40 Ω V = IR 9 V = I(40 Ω I = A 3. R P = R + R 2 + R 3 = + + R P 2 Ω 3 Ω 4 Ω = = 3 R P 2 Ω 2 Ω 2 Ω 2 Ω R P = 2 Ω 3 4. Combine Parallel (middle = + = 7 R P 0 Ω 4 Ω 20 Ω R P = 20 7 Ω Combine Serie R S = 2 Ω Ω + 3 Ω = Internal V = IR = (2 A(4 Ω = 8 V Terminal terminal = emf internal 2 V 8 V = 4 V 6. a. τ = RC 30 = R(0 F R = 3 Ω b. Q = CV Q = (9 V(0 F = 90 C Ω 2 = 7. 6

7 Phyic Unit 0: Magnetim. Know the fundamental propertie of permanent magnet. 2. Know how to induce emf. 3. Know the RHR, and Lenz Law. 4. A olenoid that i 2 m long and ha a diameter of 0.5 m ha 50 turn. Find the magnitude and direction of the magnetic field at the center of the olenoid if the current i 5 A clockwie. 5. A traight wire carrie 5 A of current. If the wire i vertical and the current run down, find the magnitude and direction of the magnetic field 2 cm from the wire. 6. A looe proton enter a magnetic field whoe direction i coming out of the page. What doe it path look like? If the path i bent, what way doe it bend? 7. The path of a charged particle i bent clockwie in a magnetic field that i pointed out of the page. What i ign of the charge of the particle? 8. The force on a 3 cm wire that carrie 0 A i 0.05 N. The wire i in a 0.5 T magnetic field. What i the angle between the wire and the magnetic field? 9. A current goe down and the magnetic field point to the right. What i the direction of the force on the wire carrying the current? 0. A ingle circular loop of wire i in a 0.5 T B-field. The normal make an angle of 30 with the B-field. If there i a 5 A current in the loop (r = 5 cm, what i the torque on the loop?. Two wire are ide by ide and very cloe to each other. One wire carrie 2 A and the other 3A in the ame direction. What i magnetic field 5 cm from the wire? 2. A circular loop of wire (r = 5 cm i in a magnetic field (B = 0.5 T with the normal of the loop parallel to the B-field. The B-field increae at a rate of 0. T/. What i the induced emf in the loop? What direction would a current flow through the loop? 3. A tranformer primary coil ha 60 turn and 240 V. How many turn are needed in the econdary coil to get 80 V? I thi a tep-up or tep-down tranformer? 4. A olenoid with 0 turn ha a cro-ectional area of 2.0 cm 2 and length of 5 cm. How much energy i tored in the magnetic field of the olenoid when it carrie a current of 5.0 A? 5. Two coil hare a common axi. The mutual inductance of thi pair of coil i 0.0 mh. If the current in coil i changing at the rate of 0 A/, what i the magnitude of the emf generated in coil 2?

8 4. L = 2 m, d = 0.5 m, N = 50, I = 5 A B = μ 0 ni; n = N = 50 = 75 m L 2 m B = (4π 0 7 Tm (75 A m (5 A = T RHR ay point into paper. Ampere Law 5. I = 5 A, r = 0.02 m B = μ 0I 2πr B = (4π 0 7Tm A 2π(0.02 m (5 A = T Goe in on left, out on right 6. Since the proton i charged, the path i bent. RHR finger - thumb in direction of v - palm point in direction of F Bend to right (electron would bend left 7. Poitive B = μ 0I 2πr B(2π0.05 m = (4π 0 7 Tm (3 A + 2 A A B(0.346 m = Tm B = T 2. N =, r = 0.05 m, B = 0.5 T, ΔB = 0. T Δt emf = N ΔΦ, Φ = BA co θ Δt emf = B fa co 0 B 0 A co 0 Δt emf = ( A(B f B 0 Δt emf = (A ΔB Δt emf = (π(0.05 m 2 (0. T = V Flux i getting tronger o induced B-field hould cancel the original B-field. RHR curl your finger through the loop in the direction of the induced B-field. Your thumb will point the direction of the current. 3. N p = 60, V p = 240 V, V = 80 V V = N V p N p 80 V = N 240 V 60 N = turn; Step-down ince V decreae. 4. L = u 0N 2 A l L = (4π Tm 0 7 A (02 ( m m = H E ind = 2 LI2 8. L = 0.03 m, I = 0 A, F = 0.05 N, B = 0.5 T F = ILB in θ 0.05 N = (0 A(0.03 m(0.5 T in θ 0.34 = in θ θ = RHR finger B - thumb I - palm F E ind = 2 ( H(5 A 2 5. emf = M ΔI 2 Δt = J emf = (0.00 H (0 A = V F i out of page 0. N =, B = 0.5 T, θ = 30, I = 5 A, r = 0.05 m τ = NIAB in θ τ = (5 A(π(0.05 m 2 (0.5 T in 30 = Nm

9 Phyic Unit : Electromagnetic Wave. Know about the pectrum of light including the complete pectrum and viible light. 2. Know about the eye, viion correction, and color viion 3. Know how to make ray diagram for mirror and lene. 4. What type of image to the variou mirror and lene make? (real or virtual (upright or inverted (enlarged or reduced 5. Why doe refraction happen? 6. A py atellite i in orbit at a ditance of m above the ground. It carrie a telecope that can reolve the two rail of a railroad track that are.4 m apart uing light of wavelength 500 nm. What i the ize of the mirror in the telecope? 7. WAUS ha a frequency of 90.7 MHz. What i it wavelength? 8. An electromagnetic wave ha a magnetic field with peak value T. What i the average intenity of the wave? 9. If the index of refraction i 2.5, what i the peed of light in the material? 0. A beam of light in a material of index of refraction of.5 hit a boundary with air (n =.00. If the angle of incidence i 25, what i the angle of refraction?. A 2 cm object i placed 5 cm from a len. The reulting image height ha a magnitude of 0.5 cm and the image i inverted. What i the focal length of the len? 2. What i the image ditance if an object i placed 0 cm in front of a concave mirror with radiu of curvature of 2 cm? 3. Light with a 700nm wavelength i hown through a double lit. If the m = 0 and m = bright fringe are eparated by 0, what i the eparation of the lit? 4. Light with a700nm wavelength i hown through a ingle lit onto a creen 3 m away. What i the width of the lit if the 2 nd -order dark fringe i located 50 cm from the center of the central bright region? 5. A diffraction grating ha 2000 line/cm and ha monochromatic light hown on it. If the 3 rd -order maximum i at 20, what i the wavelength of the light? 6. A portion of a oap bubble appear to have λ = nm in a vacuum when viewed at normal incidence in white light. Determine the mallet, non-zero thickne for the oap film if it index of refraction i Unpolarized light with an average intenity of 000 W/m 2 enter a polarizer with a vertical tranmiion axi. a. What i the intenity of the light after the polarizer? b. Then the light hit a econd polarizer. The light that exit the econd polarizer ha an intenity of 300 W/m 2. What i the orientation angle of the econd polarizer?

10 4. Mirror Concave: d o > R image real, inverted, reduced, between C and F f < d o < R image real, inverted, enlarged, beyond C d o < f image virtual, upright, enlarged, behind mirror Convex: image virtual, upright, reduced, behind mirror Lene Converging: d o > 2f image real, inverted, reduced, between 2F and F f < d o < 2f image real, inverted, enlarged, beyond 2F d o < f image virtual, upright, enlarged, behind len Diverging: image virtual, upright, reduced, behind len 5. Speed of light change 6. θ =.22 λ D.4 m tan θ = 0 5 m θ = θ =.22 λ D = m D D = m 7. f = Hz, c = m c = fλ m = ( Hzλ 8. I ave = cb 0 2 2μ 0 λ = 3. 3 m I ave = (3.00 m 08 (0.500 T2 2 (4π 0 7 T Nm I ave = W/m 2 9. n = 2.5 n = c v 2. R = 2 cm, f = 6 cm, d o = 0 cm f = d o + d i = d i = 6 0 d i d i = 5 cm 3. in θ = mλ d in 0 = ( m d d = 4.03 μm = m 4. in θ = mλ W tan θ = θ = 9.46 in 9.46 = 2( m W W = m 5. in θ = mλ d = d 2000 line cm = cm = m 3λ in 20 = m λ = m 6. Only ray phae hift o to get contructive interference, 2t = λ n 2 λ n = λ n = m = m 2.0 2t = m 2 t = m 7. a. 500 W m2 (halved b. S = S 0 co 2 θ 300 W = 500 W m 2 m 2 co2 θ 0.6 = co 2 θ = co θ θ = co = = m v v = m 0. n =.5, θ = 25, n 2 =.0, θ 2 =? n in θ = n 2 in θ 2.5 in 25 =.0 in θ = in θ θ = in = h 0 = 2 cm, d o = 5 cm, h i = 0.5 cm, f =? h i = d i h o d o = d i 5 2d i = 7.5 d i = 3.75 cm f = d i + d o = + f f = 3 cm

11 Phyic Unit 2: Special Relativity. Define inertial reference frame, proper time, dilated time, proper length, contracted length, relativitic momentum, nonrelativitic momentum, 2. Know the relativity potulate and their conequence. 3. An atronaut travel at x0 8 m/ for 24 hour a meaured by ground control. What i the time a meaured by the atronaut? 4. An alien flie by a football game at 0.90c and meaure the time it take to kick a field goal a What i the proper time for the kick? 5. A meter tick i meaured to be 50 cm long. How fat mut the meter tick be traveling? 6. What i the relativitic momentum of an electron traveling at 0.99c? 7. A car i 500 kg at ret. What i the increae in it energy when it i traveling at 0.90c? 8. How much energy will be releaed when 2 kg of pencil i converted to energy? 9. What i the ratio of relativitic kinetic energy to claical kinetic energy for a 500 kg car traveling at 0.90c? 0. The Enterprie move at 0.9c relative to earth and the Klingon Bird-of-Prey move at 0.7c relative to earth. What doe the navigator of the Bird-of-Prey report for the peed of the Enterprie?. The Klingon Battle Cruier moving at 0.7c relative to earth fire a torpedo at 0.5c relative to the Battle Cruier. What i the peed of the torpedo a oberved from earth? 2. The Klingon Battle Cruie approache earth at 0.7c relative to earth. It pae the Ferengi Shuttle at 0.5c relative to the huttle. What i the peed of the Shuttle relative to the earth? 3. The tarhip Enterprie approache the planet Ria at a peed of 0.5c relative to the planet. On the way, it overtake the intergalactic freighter Atra. The relative peed of the two hip a meaured by the navigator on the Enterprie i 0.c. If the Atra ha a red ( = 650 nm navigation light, what wavelength will the Enterprie ee a they approach the Atra.

12 3. Δt = 24 h, v = 0 8 m, Δt 0 =? Δt = Δt 0 24 h = v2 24 h = Δt 0 Δt 0 ( 08 m 2 (3 0 8 m h 8 9 = Δt 0 Δt 0 = h 4. v = 0.90c, Δt = 0.50, Δt 0 =? Δt = (0.90c = Δt 0 Δt 0 = L 0 = m, L = 0.5 m, v =? L = L 0 v2 0.5 m = m v = v = v2 v = 0.75c v = 0. 87c 6. v = 0.99c, m = kg, p =? p = mv v2 ( kg (0.99 (3 0 8 m p = (0.99c2 p = kg m/ 7. m = 500 kg, v = 0.90c, KE =? E = (2 kg (3 0 8 m 2 E = J 9. KE claic = 2 mv2 KE claic = 2 (500 kg (0.90 (3 08 m 2 KE claic = J KE relativitic = J (ee #7 ratio = J = J 0. v EntE = 0.9c, v KE = 0.7c, v EntK =? v EntK = v EntE + v EK + v EntEv EK 0.9c + 0.7c v EntK = + (0.9c( 0.7c v EntK = 0. 54c. v KE = 0.7c, v TK = 0.5c, v te =? v TE = v TK + v KE + v TKv KE 0.5c + 0.7c v TE = + (0.7c(0.5c v TE = c 2. v KE = 0.7c, v KS = 0.5c, v SE =? v SE = v SK + v KE + v SKv KE 0.5c + 0.7c v SE = + ( 0.5c(0.7c v SE = c 3. u = 0.c, λ = 650 nm λ ob = λ ( + u c u c λ ob = (650 nm ( + 0.c c 0.c = 53 nm c KE = m ( v2 KE = (500 kg( ( 0.90c2 KE = J 8. m = 2 kg, E =? E = m