Two bulbs A and B are rated 100W, 120V and 10W, 120V respectively. They are connected across a 120V source in series which bulb will consume more power?

The power consumed by a bulb is given by the formula P = V^2/R, where P is the power, V is the voltage, and R is the resistance.

Step 1: Calculate the resistance of each bulb using the formula R = V^2/P.

For bulb A, R_A = (120V)^2 / 100W = 144 ohms. For bulb B, R_B = (120V)^2 / 10W = 1440 ohms.

Step 2: When the bulbs are connected in series, the total resistance is the sum of the individual resistances.

R_total = R_A + R_B = 144 ohms + 1440 ohms = 1584 ohms.

Step 3: The total power consumed by the series circuit is given by P_total = V^2 / R_total.

P_total = (120V)^2 / 1584 ohms = 9.09W.

Step 4: The power consumed by each bulb is proportional to its resistance.

P_A = P_total * (R_A / R_total) = 9.09W * (144 ohms / 1584 ohms) = 0.82W. P_B = P_total * (R_B / R_total) = 9.09W * (1440 ohms / 1584 ohms) = 8.27W.

So, bulb B will consume more power when the two bulbs are connected in series across a 120V source.