Milliamp-hours

The amount of time it t ikes to discharge a battery depends upon the battery capacity C expressed in milliamp hours (mAh) (more is better) and the amount of current drawn by the load. Battery charge and discharge currents are normalized with respect to battery capacity and are expressed in terms of C-rate. C-rate = C/1 hour, e.g., to a 150-mAh battery has a C-Rate of 150 mA. The current corresponding to 1C is 150 mA and O.IC, 15 mA. For a given ceU type, the behavior of cells with varying capacity is similar at the same C-rate. More in depth information about batteries can be found in the Handbook of Batteries (Linden, 1995). 

SDS Electrophoresis and Gel Scanning. Samples were prepared for SDS-polyacrylamide gel electrophoresis by a lysis-toiling procedure. 2 mL of a culture sample was lysed by sonication with a Branson sonicator and microtip at setting 4 40% duty for 4 minutes. 200 microliters of the sonicate was mixed with 100 microliters of SDS loading buffer (0.3 g SDS, 0.01 g bromophenol blue, 3 mL glycerol, 1.5 mL beta-mercaptoethanol, and 1.88 mL tris-HCl(pH 6.8) per 10 mL). The mixture was toiled for 5 minutes in a microfuge tube then 20-50 microliters were loaded into a lane. The samples were separated on a 10% SDS gel with a 2% stacking buffer (18) for 5 hours at 30 milliamps. 

Q.5.9 Calculate the work performed by a battery delivering 100 milliamps at 9 volts for 2 h. How much energy is used Express the answer in (a) joules and joules-sec , (b) calories-calories and (c) watt-hours and watts. Label which units are work and which are energy. 

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