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A current is established in a discharge tube of cross section 8xx10^(-4)m^(2) when a sufficiently high potential difference (say 32 kV) is applied across the two electrodes in the tube. The gas ionises, electrons move towards the positive terminal and positive ions towards the negative terminal. What are the magnitude and sense of the current in a hydrogen discharge tube in which 3xx10^(18) electrons and 2xx10^(18) protons move past the cross - sectional area of the tube in each second? |
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Answer» Solution :The current due to electrons will be `I_(e)-(n_(e))/(t)xxq_(e)-3xx10^(18)xx1.6xx10^(-19)=0.48A` The DIRECTION of `I_(e)` current is from anode to cathode. Current due to protons will be `I_(p)=(n_(p))/(t)xxq_(p)=2xx10^(18)xx1.6xx10^(-19)=0.32A` The direction of `I_(p)` current is from anode to cathode. So, the total current is `I=I_(e)+I_(p)=0.48+0.32=0.8A`from anode to cathode of DISCHARGE tube. |
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