In a hydrogen discharge tube it is observed that through a given cross-section $3.13 \times {10^{15}}$ electrons are moving from right to left and $3.12 \times {10^{15}}$ protons are moving from left to right. What is the electric current in the discharge tube and what is its direction
A$1\,mA$ towards right
B$1\,mA$ towards left
C$2\,mA$ towards left
D$2\,mA$ towards right
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A$1\,mA$ towards right
a (a) $I = {n_e}{q_e} + {n_p}{q_p} = 1\,mA$ towards right
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