Recent content by physicsstudent14

According to my professor, adding alkali neutralizes protons so that... Adding 0.5 mol of alkali will give a pH of the carboxyl group pKa = 1.8 Adding 1.0 mol of alkali will give a pH between 1.8 and 6.0 Adding 1.5 mol of alkali will give a pH of the histidine group side chain pKa = 6.0...

Homework Statement A solution of histidine has all acid-base groups protonated. The pKa of the carboxy group is 1.8, the amino group is 9.2, and the side chain is 6.0. For each mole of amino acid, 2.5 moles of NaOH are added. What is the pH of the solution? Homework Equations...

Oh...now I understand, I hope. No = 32000 atoms = 32000 nuclei N = 32000-31000 = 1000 nuclei 1 atom = 1 nuclei t = 4 s Find halflife N/No = (0.5)^{t/halflife} log(N/No)/log(0.5) = t/halflife log(N/No)/log(0.5) = t/halflife halflife = t/log(N/No)/log(0.5) halflife =...

Homework Statement A student takes a sample of 32,000 6He atoms and measures 31000 daughter nuclei 4 seconds later. What is the half-life of 6He? What is the daughter nucleus if the 6He underwent beta minus decay? Homework Equations N = (No)(0.5)^{t/halflife} The Attempt at...

Oh, ok. That makes sense. Wow, I am so incompetent. Resistivity ρ = (rA/L) r = (ρL)/A = (1.7 x 10^(-8) Ω m)(1.2 m)/(π x 0.0005² m²) = 0.0260 Ω I = V/R = 9V/(0.1 Ω + 0.0260 Ω) = 71.4 A Net force = Magnetic Force - weight of wire - weight of battery = 0 Magnetic Force = weight of wire + weight of...

Thanks for your help, so now I get... Net force = Magnetic Force - weight = 0 LIB - mg = 0 LIB = mg Mass of the wire = (density)(volume) = (8920 kg/cubic meter)(π x 0.0005² m²)(1.2 m) = 0.0084 kg B = (mg)/(LI) = (0.0084 kg x 9.8 m/s²)/(1.2 m x 84.5 A) = 8.125 x 10^-4 T Does this look better...

Homework Statement A wire is bent into a square connected to the terminals of a 9 Volt battery. The wire is constructed of copper with diameter of 1 mm and is bent into a square with side length of 30 cm. If the battery has a mass of 50 g and internal resistance 0.1 Ω, what magnetic field...

Because V = IR, and I = V/R, then the larger current will coincide with the smaller resistance (parallel circuit). If the parallel circuit has a small resistance and larger current, then it will use up more power, so the series circuit maximizes battery life, right? Thanks.

Homework Statement Draw a circuit the involves a battery and two identical bulbs that will maximize the lifetime of the battery. More specifically, draw a circuit that allows you to run the lights longest Homework Equations P = IV V = IR Series: R = R1 + R2 Parallel: R = 1/(1/R1 +...

Thanks I think I understand it now. I just messed up on the units.

Homework Statement A 4.0-m-wide swimming pool is filled to the top. The bottom of the pool becomes completely shaded in the afternoon when the sun is 20 degrees above the horizon. How deep is the pool?Homework Equations Snell's law (n1)sin(x1) = (n2)sin(x2) Index of Refraction of Air = 1 Index...