KCET 2026 Physics Solved Paper

Concept:Electric current is taken in the direction of motion of positive charge, while for negative charge the current is opposite to its motion.Explanation:Each electron and proton carries charge $e = 1.6 \times 10^{-19}\ \mathrm{C}$.An alpha particle carries charge $+2e = 3.2 \times 10^{-19}\ \mathrm{C}$.Since $10^{19}$ electrons move to the left, the current due to electrons is toward the right:$$I_e = 10^{19} \times 1.6 \times 10^{-19} = 1.6\ \mathrm{A}.$$Since $10^{19}$ protons move to the left, the current due to protons is toward the left:$$I_p = 10^{19} \times 1.6 \times 10^{-19} = 1.6\ \mathrm{A}.$$Since $10^{19}$ alpha particles move to the right, the current due to alpha particles is toward the right:$$I_{\alpha} = 10^{19} \times 3.2 \times 10^{-19} = 3.2\ \mathrm{A}.$$Taking the right direction as positive:$$I_{\text{net}} = 1.6 + 3.2 - 1.6 = 3.2\ \mathrm{A}.$$The positive value shows the net current is directed toward the right.Answer:3.2 A towards right.Correct option: B.