A small electric immersion heater is used to heat 74 g of water for a cup of instant coffee. The heater is labeled "150 watts" (it converts electrical energy to thermal energy at this rate). Calculate the time required to bring all this water from 22°C to 100°C, ignoring any heat losses. (The specific heat of water is 4186 J/kg-K.) Number Units

A small electric immersion heater is used to heat 74 g of water for a cup of instant coffee. The heater is labeled "150 watts" (it converts electrical energy to thermal energy at this rate). Calculate the time required to bring all this water from 22°C to 100°C, ignoring any heat losses. (The specific heat of water is 4186 J/kg-K.) Number Units

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter1: Temperature And Heat

Section: Chapter Questions

Problem 121AP: An infrared heater for a sauna has a surface area of 0.050 m2 and an emissivity of 0.84. What...

See similar textbooks

Similar questions

A coal power plant consumes 100,000 kg of coal per hour and produces 500 MW of power. If the heat of combustion of coal is 30 MJ/kg, what is the efficiency of the power plant?
An infrared heater for a sauna has a surface area of 0.050 m2 and an emissivity of 0.84. What temperature must it run at if the required power is 360 W? Neglect the temperature of the environment.
An engine absorbs three times as much heat as it discharges. The work done by the engine per cycle is 50 J. Calculate (a) the efficiency of the engine, (b) the heat absorbed per cycle, and (c) the heat discharged per cycle.
In performing 100.0 J of work, an engine discharges 50.0 J of heat. What is the efficiency of the engine?
How much heat transfer occurs to the environment per day by an electrical power station that uses 1.2 * 1014 J of heat transfer into the engine with an efficiency of 42%? How much electrical energy is generated per day?
How much steam at 250°F would be required to heat 10 lb of water from 70°F to 210°F in a direct steam injection heater? The answer must be 1.42 lbs
In order not to damage the resistance in the kettles, the difference between the temperature ofthe heater and the fluid should not exceed 25 oC. If the heat transfer area between the fluid andthe heater is 78.5 cm2 and the heat transfer coefficient is 400 W/m2.K, find the maximumallowable power of the heater in order to boil water?
A 3 ohm heater takes 6 amperes while submerged in 1200 grams of water contained in a vessel with a water equivalent to 200 grams. What is the efficiency of the system if the time required for the temperature to change by 70 degrees Celsius is 3.95 hours?
How much energy (in J) is required to evaporate 25% of 4g of water currently at 100 degrees C? The answer (in fundamental SI unit) is ___________ (type the numeric value only, please do NOT use scientific notation)
A counter-flow double-pipe heat exchanger is to heat water from 20°C to80°C at a rate of 1.2 kg/s. The heating is to be accomplishedby geothermal water available at 160°C at a mass flow rate of 2 kg/s. Theinner tube is thin-walled and has a diameter of 1.5 cm. The overall heat transfercoefficient of the heat exchanger is 640 W/m2?K. Using the effectiveness–NTUmethod, determine the length of the heat exchanger required to achieve thedesired heating.
During an experiment conducted in a room at 25°C, a laboratory assistant measures that a refrigerator that draws 2 kW of power has removed 30,000 kJ of heat from the refrigerated space, which is maintained at -30°C. The running time of the refrigerator during the experiment was 20 min. Determine if these measurements are reasonable.
How much work must be done by this heat pump to supply 2550 J of heat on a day when the outside temperature is 253 K?