Complete Version 2 Quiz Solns

# Complete Version 2 Quiz Solns - Phys320 (Reshchikov) Quiz...

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Phys320 – (Reshchikov) Quiz #1: Relativity February 5, 2007 Name: __SOLUTION__ Complete both of the following problems. Show all of your work for full credit. Problem 1 The lifetime of 6 2 He is 807 ms and it is traveling at 0.9 c relative to Earth. Can it travel the distance from Moon to Earth (384,400 km) before decaying? Show your work. First, use time dilation to find the particle’s lifetime ! t in your earth frame. Then, calculate the distance it travels using its speed and lifetime in your frame. " # " # " # " # 2 2 2 8 8 8 1 1 ' 2.294 0.807s 1.851s where 2.294 1 1 0.9 0.9 3 10 m/s 1.851s 5 10 m > 3.84 10 m t t v c x v t \$ ! % ! % % % % % & & ! % ! % % Yes, the particle will travel the distance before decaying. Problem 2 A missile is launched along y axis with a speed 0.98 c from a spaceship which is moving along z axis at speed 0.9 c relative to the earth. Find the component velocities u x , u y , and u z of the missile as observed on earth. " # " # " # " # " # " # " # 2 2 2 2 2 2 2 2 2 ' ' ' ' ' ' = 0, = 0.98 , = 0. 0.9 1 1 2.294 1 0.9 1 / 0 = 0 1 / 2.294 1 0 0.9 / 0.98 = 0.427 1 / 1 0 0.9 / 0 0.9 = 0.9 1 / 1 0 0.9 / x y z x x z y y z z z z u u c u v c v c u u u v c c c c u c u c u v c c c c u v u u v c c c c ( ( ( % % % % & & % % ) * ) * + + , - . - . / 0 / 0 % % ) * ) * + + - . - . / 0 / 0 + + % % + + c S S’ v x y z z' y' x'

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Phys320 – (Reshchikov) Quiz #2: Nuclear Atom (Topic 2) February 4, 2004 Name: SOLUTIONS Complete both of the following problems. Show all of your work for full credit. Formula for X-ray lines: Problem 1 : Atomic Spectra Find the minimum energy transition for the Balmer series ( n f = 2) of Si 13+ . Calculate both the energy (eV) and 2 (nm). Sketch energy levels of an electron in Si 13+ and show this transition (w/o scale and any numbers). " # 2 0 2 2 2 2 2 where 2 for Balmer series, 3 for minimum energy, 14 for Si 14 13.6 eV 1 1 = = 1 1 370.2eV 2 3 1240eV nm 3.35 nm i i f f i f n n Z E E E Z E n n hc E 2 % ! % 3 4 5 6 & % & 5 6 7 8 3 4 & % 5 6 7 8 % % % n = 1 n = 2 n = 3 n = 9 Energy 0 Problem 2 : X-ray Emission Find the energy and wavelength of the K : X-ray line for uranium (U: Z = 92). " # " # " #" # 4 2 0 2 2 2 2 2 4 1 1 K series: 1 where 1 for K series, 1for , and 92 for U 1 1 K 13.6eV 92 1 8.45 10 eV (or 84.5 keV) 1 2 1240eV nm 0.015 nm 8.45 10 eV i f f i f E E Z n n n Z n n E hc E : 3 4 ! % & & % & % % 5 6 5 6 7 8 3 4 % & & % 5 6 7 8 % % %
Phys320 – (Reshchikov) Quiz #3: Topic 3 (Quantization of radiation) September 22, 2004 SOLUTIONS Complete both of the following problems. Show all of your work for full credit. Useful formulas Constants Stefan-Boltzmann Law R = ; T 4 e = 1.6 × 10 –19 C Wien’s Law 2 max T = 2.898 × 10 –3 mK m e = 9.1 × 10 –31 kg (0.511 MeV) Planck’s Law U( 2 ) = (8 < hc 2 –5 )/[exp(hc/ 2 kT) – 1] h = 6.626 × 10 –34 Js Photoelectric Effect eV o = hf – = hc = 1240 eV nm

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## This homework help was uploaded on 04/22/2008 for the course PHYS 320 taught by Professor Baski during the Spring '04 term at VCU.

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Complete Version 2 Quiz Solns - Phys320 (Reshchikov) Quiz...

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