How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?
Why DC power is simply voltage times current, P = E x I. Here 12 volts multiplied by 0.2 amperes gives 2.4 watts. No other formula is needed because both voltage and current are given directly.
Watch out The 24 watt choice is the answer you get by slipping a decimal place, treating the 0.2 A as 2 A; the 60 watt figure comes from dividing 12 by 0.2, which gives resistance in ohms, not power.
P = E x I. Watch the decimal: 0.2 A is one fifth of an amp, so the answer is small.