Physics For Scientists & Engineers With Modern Physics, Vol. 3 (chs 36-44) (4th Edition)
4th Edition
ISBN: 9780132274005
Author: Douglas C. Giancoli
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 25, Problem 78GP
An electric heater is used to heat a room of volume 54 m3. Air is brought into the room at 5°C and is completely replaced twice per hour. Heat loss through the walls amounts to approximately 850kcal/h. If the air is to be maintained at 20° C, what minimum wattage must the heater have? (The specific heat of air is about 0.17 kcal/kg·C°.)
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A 56 kW electric furnace measures 1.2m x 1.3m x 0.7m. When the temperature inside the furnace is 1613 ºC, a block of aluminum with a mass of 283 kg and a temperature of 18 ºC is placed inside. Assuming the heat loss from the furnace walls is 529 W/m, how long (in min) will it take to heat the block to the furnace temperature? (Specific heat of aluminum is 0.90 kJ/kg. K)
A building with an internal volume of 400 m3 is to be heated by a 30-kW electric resistance heater placed in the duct inside the building. Initially, the air in the building is at 14°C, and the local atmospheric pressure is 95 kPa. The building is losing heat to the surroundings at a steady rate of 450 kJ/min. Air is forced to flow through the duct and the heater steadily by a 250-W fan, and it experiences a temperature rise of 5°C each time it passes through the duct, which may be assumed to be adiabatic. (a) How long will it take for the air inside the building to reach an average temperature of 24°C? (b) Determine the average mass flow rate of air through the duct.
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
Chapter 25 Solutions
Physics For Scientists & Engineers With Modern Physics, Vol. 3 (chs 36-44) (4th Edition)
Ch. 25.2 - If 1 million electrons per second pass a point in...Ch. 25.3 - Prob. 1BECh. 25.4 - Return to the Chapter-Opening Question, page 651,...Ch. 25.4 - Prob. 1DECh. 25.4 - Prob. 1EECh. 25.4 - Prob. 1FECh. 25.6 - How many 60-W 120-V lightbulbs can operate on a...Ch. 25.7 - Each channel of a stereo receiver is capable of an...Ch. 25 - What quantity is measured by a battery rating...Ch. 25 - When an electric cell is connected to a circuit,...
Ch. 25 - When a flashlight is operated, what is being used...Ch. 25 - One terminal of a car battery is said to be...Ch. 25 - When you turn on a water faucet, the water usually...Ch. 25 - Can a copper wire and an aluminum wire of the same...Ch. 25 - The equation P = V2/R indicates that the power...Ch. 25 - What happens when a lightbulb burns out?Ch. 25 - If the resistance of a small immersion heater (to...Ch. 25 - Prob. 10QCh. 25 - Explain why lightbulbs almost always burn out just...Ch. 25 - Which draws more current, a 100-W lightbulb or a...Ch. 25 - Electric power is transferred over large distances...Ch. 25 - A 15-A fuse blows repeatedly. Why is it dangerous...Ch. 25 - When electric lights are operated on low-frequency...Ch. 25 - Driven by ac power, the same electrons pass back...Ch. 25 - The heating element in a toaster is made of...Ch. 25 - Is current used up in a resistor? Explain.Ch. 25 - Compare the drift velocities and electric currents...Ch. 25 - A voltage V is connected across a wire of length l...Ch. 25 - Why is it more dangerous to turn on an electric...Ch. 25 - ( A current of 1.30 A flows in a wire. How many...Ch. 25 - (I) A service station charges a battery using a...Ch. 25 - (I) What is the current in amperes if 1200 Na+...Ch. 25 - (I) What is the resistance of a toaster if 120V...Ch. 25 - (II) An electric clothes dryer has a heating...Ch. 25 - (II) A hair dryer draws 9.5 A when plugged into a...Ch. 25 - (II) A 4.5-V battery is connected to a bulb whose...Ch. 25 - (II) A bird stands on a dc electric transmission...Ch. 25 - (II) A 12-V battery causes a current of 0.60 A...Ch. 25 - (II) An electric device draws 6.50 A at 240 V. (a)...Ch. 25 - (I) What is the diameter of a 1.00-m length of...Ch. 25 - (I) What is the resistance of a 4.5-m length of...Ch. 25 - (II) Calculate the ratio of the resistance of 10.0...Ch. 25 - (II) Can a 2.2-mm-diameter copper wire have the...Ch. 25 - (II) A sequence of potential differences V is...Ch. 25 - (II) How much would you have 10 raise the...Ch. 25 - (II) A certain copper wire has a resistance of...Ch. 25 - (II) Determine at what temperature aluminum will...Ch. 25 - (II) A 100-W lightbulb has a resistance of about...Ch. 25 - (II) Compute the voltage drop along a 26-m length...Ch. 25 - (II) Two aluminum wires have the same resistance....Ch. 25 - (II) A rectangular solid made of carbon has sides...Ch. 25 - (II) A length of aluminum wire is connected to a...Ch. 25 - (II) Small changes in the length of an object can...Ch. 25 - (II) A length of wire is cut in half and the two...Ch. 25 - (III) For some applications, it is important that...Ch. 25 - (III) Determine a formula for the total resistance...Ch. 25 - (III) The filament of a lightbulb has a resistance...Ch. 25 - (III) A 10.0-m length of wire consists of 5.0 m of...Ch. 25 - (III) A hollow cylindrical resistor with inner...Ch. 25 - (I) What is the maximum power consumption of a...Ch. 25 - (I) The heating element of an electric oven is...Ch. 25 - (I) What is the maximum voltage that can be...Ch. 25 - (I) (a) Determine the resistance of, and current...Ch. 25 - (II) An electric power plant can produce...Ch. 25 - (II) A 120-V hair dryer has two settings: 850 W...Ch. 25 - (II) A 115-V fish-tank heater is rated at 95W....Ch. 25 - (II) You buy a 75-W lightbulb in Europe, where...Ch. 25 - (II) How many kWh of energy does a 550-W toaster...Ch. 25 - (II) At 0.095/kWh, what does it cost to leave a...Ch. 25 - (II) What is the total amount of energy stored in...Ch. 25 - (II) An ordinary flashlight uses two D-cell 1.5-V...Ch. 25 - (II) How many 75-W lightbulbs, connected to 120V...Ch. 25 - (II) An extension cord made of two wires of...Ch. 25 - (II) A power station delivers 750kW of power at...Ch. 25 - (III) A small immersion heater can be used in a...Ch. 25 - (III) The current in an electromagnet connected to...Ch. 25 - (III) A 1.0-m-long round tungsten wire is to reach...Ch. 25 - (I) Calculate the peak current in a 2.7-k resistor...Ch. 25 - (I) An ac voltage, whose peak value is 180 V, is...Ch. 25 - (II) Estimate the resistance of the 120-Vrms...Ch. 25 - (II) The peak value of an alternating current in a...Ch. 25 - (II) An 1800-W are welder is connected to a...Ch. 25 - (II) (a) What is the maximum instantaneous power...Ch. 25 - (II) A heater coil connected to a 240-Vrrms ac...Ch. 25 - (II) For a time-dependent voltage V(t), which is...Ch. 25 - Prob. 57PCh. 25 - (II) A 5.80-m length of 2.0-mm-diameter wire...Ch. 25 - (II) At a point high in the Earths atmosphere....Ch. 25 - (I) What is the magnitude of the electric field...Ch. 25 - (II) A neuron is stimulated with an electric...Ch. 25 - (III) During an action potential, Na+ ions move...Ch. 25 - A person accidentally leaves a car with the lights...Ch. 25 - How many coulombs are there in 1.00 ampere-hour?Ch. 25 - You want to design a portable electric blanket...Ch. 25 - What is the average current drawn by a 1.0-hp...Ch. 25 - Prob. 67GPCh. 25 - The heating element of a 110-V, 1500-W heater is...Ch. 25 - (a) A particular household uses a 1.8-kW healer...Ch. 25 - A small city requires about 15 MW of power....Ch. 25 - A 1400-W hair dryer is designed for 117 V. (a)...Ch. 25 - The wiring in a house must be thick enough so it...Ch. 25 - Prob. 73GPCh. 25 - Suppose a current is given by the equation I =...Ch. 25 - A microwave oven running at 65% efficiency...Ch. 25 - Prob. 76GPCh. 25 - 220 V is applied to two different conductors made...Ch. 25 - An electric heater is used to heat a room of...Ch. 25 - A 2800-W oven is connected to a 240-V source, (a)...Ch. 25 - A proposed electric vehicle makes use of storage...Ch. 25 - A 12.5- resistor is made from a coil of copper...Ch. 25 - A fish-tank heater is rated at 95 W when connected...Ch. 25 - A 100-W, 120-V lightbulb has a resistance of 12 ...Ch. 25 - In an automobile, the system voltage varies from...Ch. 25 - The Tevatron accelerator at Fermilab (Illinois) is...Ch. 25 - Lightbulb A is rated at 120 V and 40 W for...Ch. 25 - An air conditioner draws 14 A at 220-V ac. The...Ch. 25 - Copper wire of diameter 0.259 cm is used to...Ch. 25 - Battery-powered electricity is very expensive...Ch. 25 - How far does an average electron move along the...Ch. 25 - A copper pipe has an inside diameter of 3.00 cm...Ch. 25 - For the wire in Fig. 2539, whose diameter varies...Ch. 25 - The cross section of a portion of wire increases...Ch. 25 - Prob. 94GPCh. 25 - The level of liquid helium (temperature 4 K) in...Ch. 25 - (II) The resistance, R, of a particular thermistor...
Additional Science Textbook Solutions
Find more solutions based on key concepts
7. In the circuit shown in Figure 19.42, resistor A has three times the resistance of resistor B. Therefore.
F...
College Physics (10th Edition)
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective
The speed of the person sitting on the chair relative to the chair and relative to Earth.
Conceptual Physics (12th Edition)
The pV-diagram of the Carnot cycle.
Sears And Zemansky's University Physics With Modern Physics
52. * Somebody tells you that Figure P7.52 shows a displacement-versus-time graph of two carts on a linear tra...
College Physics
44. 50 pJ of energy is stored in a 2.0 cm × 2.0 cm × 2.0 cm region of uniform electric field. What is the elect...
College Physics: A Strategic Approach (4th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- An electric kitchen range has a total wall area of 1.40 m2 and is insulated with a layer of fiberglass 4.0 cm thick. The inside surface of the fiberglass has a temperature of 175 degrees C and its outside surface is at 35 degrees C. The fiberglass has a thermal conductivity of 0.040 W/(m*K). What is the heat current through the insulation, assuming it may be treated as a flat slab with an area of 1.40 m2? What electric-power input to the heating element is required to maintain this temperature?arrow_forwardHow 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?arrow_forwardLight bulb 1 operates with a filament temperature of 2900 K, whereas light bulb 2 has a filament temperature of 2000 K. Both filaments have the same emissivity, and both bulbs radiate the same power. Find the ratio A1/A2 of the filament areas of the bulbs.arrow_forward
- One way to keep the contents of a garage from becoming too cold on a night when a severe subfreezing temperature is forecast is to put a tub of water in the garage. If the mass of the water is 122 kg and its initial temperature is 24.2°C, how much energy must the water transfer to its surroundings in order to freeze completely? The specific heat of water is 4186 J/kg·K, and the latent heat of fusion is 333 kJ/kg.arrow_forwardA well-sealed room contains 60 kg of air at 200 kPa and 25°C. Now solar energy enters the room at an average rate of 0.8 kJ/s while a 120-W fan is turned on to circulate the air in the room. If heat transfer through the walls is negligible, the air temperature in the room in 30 min will bearrow_forwardTo heat a room with dimensions width a=3 m, length b=5 m, height h=2,2 m, approximately an electrical power of P=10 W per square meter is needed. At a cost of 0.2 soles per kW.h, how much will it cost per day to use this heater?arrow_forward
- In a certain solar house, energy from the Sun is stored in barrels filled with water. In a particular winter stretch of five cloudy days, 1.00* 10^6 kcal is needed to maintain the inside of the house at 22.0 C. Assuming that the water in the barrels is at 50.0 C and that the water has a density of 1.00 * 10^3 kg/m3, what volume of water is required?arrow_forwardIn a one-shell and two-tube heat exchanger, cold water with inlet temperature of 20°C is heated by hot water supplied at the inlet at 80°C. The cold and hot water flow rates are 5000 kg/h and 10,000 kg/h, respectively. If the shelland- tube heat exchanger has a UAs value of 11,600 W/K, determine the cold water and hot water outlet temperatures. Assume cpc = 4178 J/kg·K and cph = 4188 J/kg·K.arrow_forwardThe Earth intercepts 1.27 × 1017 W of radiant power from the Sun. Suppose the Earth, of volume 1.08 × 1021 m3, was composed of liquid water. How long would it take for the liquid water Earth at 0 ◦C to reach liquid water at 23.8 ◦C, if none of the power was radiated or reflected back out into space? Hint: There are 3.154 × 107 s in one year. The density of water is 10 × 103 kg/m3 and the specific heat of water is 4186 J/(kg K). a)113 years b)2.69 × 104 years c)1.13 × 105 years d)2.69 × 107 years e)26.9 yearsarrow_forward
- How much fiberglass insulation (k = 0.035 W/m*K) is needed to guarantee that the outside temperature of a kitchen oven will not exceed 43 degrees Celsius? The maximum oven temperature to be maintained by the conventional type of thermostatic control is 290 degrees Celsius, the kitchen temperature may vary from 15 to 33 degrees Celsius, and the average heat transfer coefficient between the oven surface and the kitchen is 12 W/m2*K.arrow_forwardA counter-flow double-pipe heat exchanger is to heat water from 20°C to 80°C at a rate of 1.2 kg/s. The heating is to be accomplished by geothermal water available at 160°C at a mass flow rate of 2 kg/s. The inner tube is thin-walled and has a diameter of 1.5 cm. If the overall heat transfer coefficient of the heat exchanger is 640 W/m2?K, determine the length of the heat exchanger required to achieve the desired heating.arrow_forwardImagine a person standing naked in a room at 19.1°C. The walls are well insulated, so they also are at 19.1°C. The person’s surface area is 2.20 m2, and his basal metabolic rate is 2167 kcal/day. His emissivity is 0.970. If the person’s skin temperature were 38.2°C (the same as the internal body temperature), at what net rate would heat be lost through radiation? (Ignore losses by conduction and convection.)arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Heat Transfer: Crash Course Engineering #14; Author: CrashCourse;https://www.youtube.com/watch?v=YK7G6l_K6sA;License: Standard YouTube License, CC-BY