Power,P= I^2R
Since power is directly proportional to resistance R, the bulb with greater power will have greater resistance.
A 100-watt lamp glows brighter than a 25-watt lamp. What do you know about the resistances of these two lamps?
2 answers
P₁₀₀>P₂₅ =>
U²/R₁₀₀ > U²/R₂₅.
Since U = const =>
R₂₅>R₁₀₀
U²/R₁₀₀ > U²/R₂₅.
Since U = const =>
R₂₅>R₁₀₀