Explanation: \(\text{Solve: } \vec{E} = (3\hat{i} + 4\hat{j}) \, \text{NC}^{-1}\) \(E = \sqrt{3^2 + 4^2} = 5 \, \text{NC}^{-1}\) \(a = \frac{qE}{m}\) \(\phantom{a} = \frac{2 \times 1.6 \times 10^{-19} \times 5}{4 \, \text{amu}}\) \(\phantom{a} = \frac{2 \times 1.6 \times 10^{-19} \times 5}{4 \times 1.66 \times 10^{-27}}\) \(\phantom{a} = 2.4 \times 10^8 \, \text{ms}^{-2}\) \(\text{Ans. (D)}\)