Q.
In a gas discharge tube if 3×1018 electrons are flowing per sec from left to right and 2×1018 protons are flowing per second from right to left through a given cross section. The magnitude and direction of current through the cross section
As current is rate of flow of charge in the direction in which positive charge will move, the current due to electron will be ie=tneqe==3×1018×1.6×10−19= 0.48A (Opposite to the motion of electrons, i.e. right to left)
Current due to protons ip=tnpqp=2×1018×1.6×10−19=0.32A (Right to left) so total I=ie+ip=0.48+0.32=0.80A (Right to left) Hence correct answer is d