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An electric heater is used to boil small amounts of water and consists of a 18-Ω coil that is immersed directly in the water. It operates from a 120-V socket. How much time is required for the heater to raise the temperature of 0.71 kg of water from 15 °C to the normal boiling point? Take the specific heat capacity of water to be 4186 J/(kg·C°).

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gilcarusolautaro

Answer:

Is required 5.26 min to raise the temperature.

Explanation:

R= 18 ohms

V= 120 volts

m= 0.71 kg

C= 4186 J/kg °C

T1= 15°C

T2= 100 °C

Q= m * C * (T2-T1)

Q= 252.62 *10³ J

V/R= I

I= 6.66 A

P= I² * R

P= 800 W = 800 J/s

P= Q/t

t= Q/P

t= 315.77 s = 5.26 min

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