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Four cubic meters of water is to be heated by means of four 1.5 kW, 230 V immersion heating elements. Assuming the efficiency of the heater as 90%, determine the time required boiling the water if the initial temperature is 20°C and if all four elements are connected in parallel.
An electric water heater has a rating of 1 kW, 230 V. The coil used as the heating element is 10m long and has a resistivity of 1.724 x 10^-6 ohm-cm. Determine the required diameter of the wire in mils?
In an electric heater the inlet temperature is 15°C, water is flowing at the rate of 300 grams per minute. The voltmeter measuring voltage across the heating element reads 120 volts and an ammeter current taken reads 10 amperes. When steady state is finally reached, what is the final reading of the outlet thermometer?
The power drawn by a resistive coil made of copper wire is 220 W at 100 V and 20 °C. Calculate the power consume by the coil at 115 V and 100°C. The temperature coefficient of resistance at 20°C is 0.00393.
If a resistor rated at 5 watts and 6 volts are connected across a battery with an open circuit voltage of 6 volts, what is the internal resistance of the battery if the resulting current is 0.8 A?
An arc lamp takes 10A at 50V. A resistance R is to be place in series so that the lamp may burn correctly from a 110V supply. Find the power wasted in this resistor.
A resistive coil draws 2A at 110 V after operating for a long time. If the temperature rise is 55°C above the ambient temperature of 20°C, calculate the external resistance which must be initially connected in series with the coil to limit the current to 2A. The temperature coefficient of the material of the coil is 0.0043 per °C at 20°C.
The hot resistance of an incandescent lamp is 10 ohms and the rated voltage is 50 V. Find the series resistance required to operate the lamp from an 80 V supply.
Nichrome ribbon resistor elements each has a resistance of 1Ω. The element is made from sheet of nichrome alloy, 0.025 cm thick. If the width of the ribbon is 0.3 cm, what length is required per element? Assume specific resistance of nichrome alloy to be 109 micro Ω-cm.
Use the fourth-order Taylor series method to solve the initial value problem dy/dx = 3x + y^2,
y(0)=1 to approximate y(0.72), y(0.72+0.72), y(0.(3×72), y(0.(4×72)).
