A steel bucket contains 4 liters of water at 128C. An electric immersion heater rated at 1400 Watts is placed in the * Indicates an advanced

Question

A steel bucket contains 4 liters of water at 128C. An electric immersion heater rated at 1400 Watts is placed in the * Indicates an advanced level in solving. Problems 61 62 CHAPTER 1 Introduction bucket. Determine how long it will take for water to heat to 708C. Assume that the empty bucket weighs 1.1 kg. The specific heat of steel is 0.46 kJ/(kg 8C). Use an average specific heat of water of 4.18 kJ/(kg 8C). Disregard any heat loss to the surroundings.

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Hải Đăng 4 years 2021-09-02T03:28:13+00:00 1 Answers 115 views 0

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  1. Orla
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    2021-09-02T03:29:13+00:00
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    Answer:

    The time is 0.713 sec.

    Explanation:

    Given that,

    Weight of water = 4 liters

    Initial temperature = 128°C

    Power = 1400 Watts

    Final temperature = 708°C

    Weight = 1.1 kg

    Specific heat of steel = 0.46 kJ/kg°C

    Specific heat of water = 4.18 kJ/kg°C

    We need to calculate the heat gained by bucket

    Using formula of heat

    Q_{b}=mc\Delta T

    Put the value into the formula

    Q_{b}=1.1\times0.46\times(70-12)

    Q_{b}=29.348\ kJ

    We need to calculate the heat gained by water

    Using formula of heat

    Q_{w}=mc\Delta T

    Put the value into the formula

    Q_{w}=4\times4.18\times(70-12)

    Q_{w}=969.76\ kJ

    We need to calculate the total heat

    Using formula of heat

    Q=Q_{b}+Q_{w}

    Put the value into the formula

    Q=29.348+969.76

    Q=999.108\ kJ

    We need to calculate the time

    Using formula of time

    t=\dfrac{Q}{P}

    Put the value into the formula

    t=\dfrac{999.108}{1400}

    t=0.713\ sec

    Hence, The time is 0.713 sec.

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