JAMB - Physics (2025 - No. 29)
How long will it take to heat 4 kg of water from 30ºC to 65ºC using an electric kettle taking 5 A from a 240 V supply?
(Specific heat capacity of water = 4200 J kg\(^{-1}\) K\(^{-1}\))
(Specific heat capacity of water = 4200 J kg\(^{-1}\) K\(^{-1}\))
160 s
245 s
490 s
150 s
説明
Answer: C
Time = \(\frac{(mcΔT)}{(VI)}\) = \(\frac{588000}{1200}\) = 490 s.