The vending machine identifies the value of the coin by measuring the resistance of the coin.
The power dissipated by the coin is 340 mW when the current in the coin is 0.75 A.
Calculate the resistance of the coin.
Use the Physics Equations Sheet.

The question asks to calculate resistance (R) given power (P) and current (I). The formula linking these is P = I²R. Step 1: Convert the power to standard units. The power is given as 340 mW. The standard unit for power is the Watt (W). The prefix "m" (milli) means 10⁻³ or divide by 1000. So, P = 340 mW = 340 / 1000 W = 0.340 W. Step 2: The current is given in Amperes (A), which is the standard unit. I = 0.75 A. Step 3: Rearrange the formula to make R the subject. P = I²R => R = P / I² Step 4: Substitute these values into the equation. R = 0.340 W / (0.75 A)² R = 0.340 / 0.5625 R = 0.60444... Ω Rounding to two significant figures gives R = 0.60 Ω.