To calculate the current density in the electrochemical cell, we need to consider the total surface area of both electrodes and the current passing through them. The current density J is defined as the current I divided by the surface area A of the electrode:J = I / AFirst, we need to convert the surface areas of the copper and silver electrodes from cm to m:Copper electrode surface area: 25 cm * 1 m / 10,000 cm = 0.0025 mSilver electrode surface area: 10 cm * 1 m / 10,000 cm = 0.0010 mNext, we need to find the total surface area of both electrodes:Total surface area A_total = 0.0025 m + 0.0010 m = 0.0035 mNow, we can calculate the current density J using the given current I = 2.5 A and the total surface area A_total = 0.0035 m :J = I / A_total = 2.5 A / 0.0035 m = 714.29 A/mSo, the current density in the electrochemical cell is approximately 714.29 A/m.