Question

An electric iron is rated 1100W, 220V. Calculate: (i) resistance of the iron (ii) current it draws.
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Answer 1

Explanation:

• Power (P) = 1100 W
• Voltage (V) = 220 V
• Resistance (R) = ?
• Current (I) = ?

P = V²/R

R = V²/P

R = (220)²/ 1100

R = 220× 220 / 1100

R = 44 ohm

P = V I

I = P / V

I = 1100 / 220

I = 5 A

Answer 2

Answer:

I = 5A

Explanation:

==>Power P= 1100w

==>(voltage)V =220

==>R = ?

==>I=?

$p = \frac{ {v}^{2} }{ {r}^{2} } \\ r = \frac{ {v}^{2} }{p} \\ r =220 \times \frac{ {220}^{} }{1100} \\ r = 44ohm$

===>p = v/I

===>I =P/V

===>I = 1100/220

===>I = 5A