Formula Sheet for Stage 6 Physics

HSC Course (Options)Formula Name Comments Typical Problem Typical AnswerZ = ρυAcoustic2Z = ρυ = 0.003X650 = 1.95kgmsImpedance9.6.1IIro=[ Z2− Z1][ Z + Z ]2dM = m − 5log( )10122( = R)I AI B=100(M B − M A )/5m 1+ m 2= 4π 2 r 3GT1λ = R ⎛ 12 − 1 ⎞⎜2 ⎟⎝ n f n i ⎠ReflectionIntensity9.6.1AstronomicalDistance9.7.4Ratio of intensity9.7.4Kepler’s ThirdLaw9.7.5Ryberg’sequation9.8.1Z = Acoustic impedance (kgm 2 s -1=Rayls)ρ = acoustic density (kgm)υ = speed of sound in medium(m/s)I i =initial intensityI o = output intensityZ 2 = acoustic impedance(medium 1)Z 1 = acoustic impedance(medium 2)M = absolute magnitudem = relative magnituded = distance in parsecs55 = 100 = 5.02I A,B = intensity of objects A and BM A,B = absolute magnitude of A& B55 = 100 = 5.02r = radius of motion (m)T = period of motion (s)G = universal gravitation constant(6.67 X 10 -11 Nm 2 kg -2 )M 1 +M 2 = total mass of system(kg)λ = wavelength (m)n i,f = quantum states (shells)R = Ryberg’s constant 1.10 X 10 7m -1What is the acousticimpedance of vaseline giventhat its acoustic density is0.003 kgm and the speed ofsound in vaseline is 650 m/s?What is the reflection intensityat the interface of air (acousticimpedance = 0.5 kgm 2 s -1 ) andvaseline (Z=1.95 kgm 2 s -1 )?How far away is a star thatappears m=4.5 on Earth whileits absolute magnitude is –3.4?How much dimmer is Sirius A(M=-4.3) compared to Echelon(M=-2.1)?Sirius A and B orbit each otherevery 61 years. What is theradius of this orbit if Sirius Ahas a mass of 10 27 kg andSirius B is 10 29 kg?What wavelength of light isproduced in hydrogen by atransition between the first andfourth orbitals (shells)?IIro=[ Z2− Z1][ Z + Z ]M = m − 5 log(214.5−(−3.4)1+5. 021022d10d =I A=100(M B − M A )/5I B(1.95 − 0.5)=(1.95 + 0.5)) ∴d= 1022m−M1+5.02= 143parsec s−1= 0.35T = 61 X 365.25 X 24 X 60 X 60= 1925013600 s2 34πr GT(m31+ m2m1+ m2= ∴r=2GT4π−11276.67X10X1925013600(10+ 10r = 324πr = 6.9 X 10 9 m1 ⎛ 1 1 ⎞7 1 1= R⎜− ⎟ = 1.1X10X ( − )⎜2 2⎟2 2λ⎝ n n ⎠4 1f i∴λ =1.1X1071 −81(24= 9.7X101− )21m29)