In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. Water Thermometer Stirring rod Metal- sample 2003 Thomson-Brock/Cal Since the cup itself can absorb energy, a separate experiment is needed to determine the heat capacity of the calorimeter. This is known as calibrating the calorimeter and the value determined is called the calorimeter constant. One way to do this is to use a common metal of known heat capacity. In the laboratory a student heats 99.55 grams of copper to 98.18 °C and then drops it into a cup containing 83.88 grams of water at 21.14 °C. She measures the final temperature to be 28.69 °C. Using the accepted value for the specific heat of copper (See the References tool), calculate the calorimeter constant. Calorimeter Constant = J/°C

Chapter 7 homework The voltage output from a J-type thermocouple referenced to 0°C is to be used to measure temperatures from 50 to 70°C. The output voltages vary linearly over this range from 2.585 to 3.649 mV. a. If the thermocouple voltage is input to a 12-bit AD converter having a +5-V range, estimate the percent quantization error in the digital value. b. If the analog signal can be first passed through an amplifier circuit, compute the amplifier gain required to reduce the quantization error to 5% or less. c. If the ratio of signal-to-noise level (SNR) in the analog signal is 40 dB, compute the magnitude of the noise after amplification. Discuss the results of 7.40b in light of this.

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Student A observes 25 protons and 13 electrons before the conduct of experiment, after which decides to make the system neutral. How many atoms did he need to add to achieve this? O A. 12 protons O B. -13 protons O C. 12 electrons D. -13 electrons

You are working in a condensed-matter laboratory for your senior project. Several of the ongoing projects use liquid helium, which is contained in a thermally insulated vessel that can hold up to a maximum of Vmax = 240 L of the liquid at Tc = 4.20 K. Because some of the liquid helium has already been used, someone asks you to check to see if there is enough for the next day, on which four different experimental groups will need liquid helium. You are not sure how to measure the amount of liquid remaining, so you insert an aluminum rod of length L = 2.00 m and with a cross-sectional area A = 2.50 cm2 into the vessel. By seeing how much of the lower end of the rod is frosted when you pull it out, you can estimate the depth of the liquid helium. After inserting the rod, however, one of the experimenters calls you over to perform a task and you forget about the rod, leaving it in the liquid helium until the next morning. How much liquid helium is available for the next days experiments? (Aluminum has thermal conductivity of 3 100 W/m K at 4.20 k; ignore its temperature variation. The density of liquid helium is 125 kg/m3.) Assume that gaseous helium can escape from the top of the vessel.

Integrated Concepts If you want to cook in water at 150C, you need a pressure cooker that can withstand the necessary pressure. (a) What pressure is required for the boiling point of water to be this high? (b) If the lid of the pressure cooker is a disk 25.0 cm in diameter, what force must it be able to withstand at this pressure?

Integrated Concepts (a) Calculate the rate in watts at which heat transfer through radiation occurs (almost entirely in the infrared] from 1.0 m2of the Earth’s surface at night. Assume the emissivity is 0.90, the temperature of the Earth is 15°C, and that of outer space is 2.7 K. (b) Compare the intensity at this radiation with that coming to the Earth from the Sun during the day, which averages about 800 W/m2, only hall of which is absorbed. (c) What is the maximum magnetic field strength in the outgoing radiation, assuming it is a continuous wave?

Metals are malleable and ductile because a. of close-packed arrangement of atoms b. when heat touches the metal, the loosely bonded electron vibrates easily and radiate the heat with the same frequency and wavelength c. the electrons are mobile d. of the strength of the electrostatic attraction between the metal ions and electrons

1. a six inch wafer of ic that measure 2mm *3mm is fabricated using a process with seven crutical steps and a total density of 5 cm^-2 a) What is the probability that a single IC will have a defect b) What is the probability that a single IC will have two defect.

A monocrystalline silicon solar panel (active area: 1m2 )has an energy conversion efficiency of 20%. What is the power output when irradiance of 800 W/m2 is shining on the solar panel? a. 320 W. b. 80 W. c. 240 W. d. 160 W. e. 400 W.