Simplified Computation on Nuclear Decay This work by

Simplified Computation on Nuclear Decay 核衰變的簡單計算 香港理 大學 應用科學及紡織學院 應用物理學系 季宇飛 This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Source of C-14 碳十四的來源 Cosmic Rays 宇宙射線 Air neutron This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Carbon Cycle 碳循環 Atmosphere Fossil Fuels Carbon Animals Plants This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

C-14 Atoms in a Dog’s Body Input Output C-14 from the outside C-14 decay This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Decay of Carbon-14 atoms 碳十四的衰變 Decay of C-14 : Unstable Stable N(t), No. of C-14 atoms λ is constant This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Decay of Carbon-14 atoms 碳十四的衰變 No. of Atoms N 0 No. of C-14 No. of N-14 Time This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Decay of C-14 碳十四衰變 N 0 Number of C-14 Atoms 1250 0. 5 N 0 1000 750 0. 25 N 0 500 半衰期: 5730 years 250 0 0 5700 No. of C-14 Atoms Time(Year) 11400 17100 Time This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Age of the Dead Body ln No. of C-14/kg (Alive and Past), N 0 No. of C-14/kg (Dead and Now), Age= λ(constant) Nt This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Reasons for C-14 Level change C-14 in the living body N 0 C-14 in the air Cosmic Rays Magnetic field of the Earth, Solar activity…. . This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

History of Carbon-14 Level in the Air 歷史上空氣中碳十四之含量 C-14 level for different years 1940 1930 1920 This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

History of Carbon-14 Level in the Air 歷史上空氣中碳十四之含量 N 0 of 1950 Change of C-14 (%) Year This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Age of the Dead Body Age= N 0 , Alive ln Nt , Now Nt = /kg λ(constant) 1950 1700 10% Change for N 0 = /kg, Age=11500 years /kg, Age=12000 years /kg, Age=11000 years Error About 1000 years difference This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Two-decay Process Isotope 1 Isotope 2 Isotope 3 This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

A Typical Two-decay Process 典型的兩次衰變過程 No. of Atoms Isotope 1 Isotope 2 Isotope 3 Number of all Time This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK

Thank you for listening! This work by Ji Yufei of the Department Applied Physics, The Hong Kong Polytechnic University is licensed under a Creative Commons Attribution. Non. Commercial-Share. Alike 3. 0 Hong Kong License To view a copy of this license, visit http: //creativecommons. org/licenses/by-nc-sa/3. 0/hk/deed. en_HK