Question

Compare the amount of current used by a 750-W microwave oven and a 1000-W microwave oven if they both operate in a 120-V circuit.

Answer 1

The current used by the 750-W microwave is 0.75 times the current used by the 1,000-W microwave

Step-by-step explanation:

The given parameters are;

The electrical power of one of the microwaves, P₁ = 750 W

The electrical power of the other microwave , P₂ = 1,000 W

The applied voltage of the circuit = 120-V

Electric power, P = I·V

Where;

I = The amount of current used

V = The applied voltage = 120 V

Therefore, for the first microwave, we have;

P₁ = I₁ × V

∴ I₁ = P₁/V = 750 W/(120-V) = 25/4 amperes = 6.25 amperes

The amount of current used by the 750-W microwave, I₁ = 6.25 amperes

For the second microwave, we have;

P₂ = I₂ × V

∴ I₂ = P₂/V = 1,000 W/(120-V) = 25/3 amperes = 8.
`\overline 3` amperes

The amount of current used by the 1,000-W microwave, I₂ = 8.
`\overline 3` amperes.

The ratio of the two currents, is I₂/I = (25/3 amperes)/(25/4 amperes) = 4/3

Therefore, I₂ = 4/3 × I₁, from which we have;

I₁ = 3/4·I₂

The current used by the 750-W microwave is 3/4 the current used by the 1,000-W microwave.