The spectrum from a hydrogen vapour lamp is measured and four lines in the visible light range are observed. these lines are the so-called balmer series, where an electron makes a transition from a higher level to the second energy level (n 2) from the measurements of the wavelengths of these four lines, four determinations of the rydberg constant r were made. these are: for ny 3, r 10.33 um1 11.52 um for n 4, r for ny 5, r 10.23 um for ny 6, r 9.36 um an average value of r can be found. calculate the uncertainty in this average r (use the mean error technique). express you answer in um to two decimal places. it is not necessary to specify the units

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

answer; how far out of place which the object finished relative to the starting location;

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me