A. 5.0×105 J
B. 3.0×105 J
C. 1.0×105 J
D. 5.0×104 J
E. 3.0×104 J
সঠিক উত্তরঃ C. 1.0×105 J
Explanation: \(\frac{E_{k2}}{E_{k1}} = \frac{V_2^2}{V_1^2} \implies E_{k2} = \left(\frac{20}{40}\right)^2 \times 2 \times 10^5 = 5 \times 10^4 \, \mathrm{J}\) \(\text{Ans. (D)}\)