Question

In electric dryer consumes 6.0×10 6 jewel of energy when operating at 220 V for 30 minutes. During operation the dryer draws a current of approximately?

Answer 1

W = 6 · 10^6 J (side note - it's joule, not jewel)

U = 220 V

t = 30 min = 1800 sec

I = ?

We'll start from the electric energy equation:

W = U · I · t

Now to get the I, we need to divide both sides of the equation by (U · t):

I = W / (U · t)

Now, let's see if our data is in SI units. Work (same as energy) in joules and voltage in volts are OK. Time needs to be converted into seconds:

t = 30 min = 30 * 60 sec = 1800 sec

Now we're ready to insert our data:

I = 6,000,000 [J] / (220 [V] · 1800 [s]) = 6,000,000 [J] / 396,000 [V·s] ≈ 15 [A]

Answer: The dryer draws approx. 15 amperes.