Electric potential electric potential answer answer 0

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Unformatted text preview: et’s turn to the definition of electric potential: ΔV!=!ΔU/q2 Answer Define a coordinate system. Choose where the electron starts it motion as x!=!0 and its direction of motion as +x. Electric Potential Electric Potential Answer Answer 0 = ∆K + ∆U ∆K = −∆U ∆U = q 2 ∆V ∆U = (−1.6 × 10−19 C)(+5000 V) = −8.0 × 10−16 J So, the electron lost potential energy by moving in this electric field. Where did this energy go? It went into the kinetic energy of the system, since the electric force is a conservative force. We can then turn to conservation of energy to solve for the final velocity of the electron. Did any energy leave the system? No, it stays with electron. +x v= ￿ −2∆U = m ￿ 1 mv 2 = −∆U 2 −2(−8 × 10−16 J) = 4.2 × 107 m/s −31 kg 9.11 × 10 Wow! The electron got almost close to the speed of light, with just a 5000!V difference. electron Volt It becomes very inconvenient to work with Joules when you are dealing with electrons or protons. We then introduce a new unit, the electron Volt. The electron Volt (eV) is defined as the energy that an electron gains when accelerated through a potential difference of 1Volt. 1eV!=!1.602x10–19J An electron in a normal atom has about 10!eV while gamma rays (light) may have millions of eV....
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This note was uploaded on 03/16/2014 for the course PHYS 1B taught by Professor Briankeating during the Spring '07 term at UCSD.

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