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An electric kettle has a power rating of 2.4kW. How long does it take the kettle to heat up 4.5kg of tap water from 28°C to 100°C ? (c of water = 4200Jkg1°C-) What assumption must you make to arrive the answer ?

pls helppp....

Respuesta :

nuralfaqih

Assumption :

- The process is adiabatic

- Heat from electric kettle is constant

- Efficiency of electric kettle is 100%

Q = m • c • ∆T

P • t = m • c • ∆T

2400t= (4.5 kg)(4200 J/kg°C)(100°C - 28°C)

2400t = 1360800

t = 567 s

t = 9.45 min

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