Balmer Series Definition in Science

Balmer Series Definition in Science The Balmer series is the portion of the emission spectrum of hydrogen that represents electron transitions from energy levels n 2 to n 2. These are four lines in the visible spectrum. They are also known as the Balmer lines.The four visible Balmer lines of hydrogen appear at 410 nm, 434 nm, 486 nm and 656 nm. These are caused by photons produced by electrons in excited states transitioning to more stable energy levels. There are also multiple ultraviolet Balmer lines that have wavelengths shorter than 400 nm. The spectrum becomes continuous approaching 364.6 nm (ultraviolet). Note: While Balmer discovered four visible lines, five other hydrogen spectral series were later discovered for values of n besides 2. The Balmer series in especially important in astronomy. The lines are seem emitted by many stellar objects because most of the universe consists of the element hydrogen. The series is used to help determine the surface temperature of stars. Source Nave, C. R. (2006). Hydrogen Spectrum. HyperPhysics. Georgia State University.

Defining Power in Physics

Defining Power in Physics Power is the rate at which work is done or energy  is transferred in a unit of time. Power is increased if work is done faster or energy is transferred in less time. Calculating Power The equation for power is P W/t P stands for power (in watts)W stands for the amount of work done (in Joules) or energy expended (in Joules)t stands for the amount of time (in seconds) In calculus terms, power is  the derivative of work  with respect to time. If work is done faster, power is higher. If work is done slower, power is smaller. Since work is force times displacement (WF*d), and velocity is displacement over time (vd/t), power equals force times velocity: P F*v. More power is seen when the system is both strong in force and fast in velocity. Units of Power Power is measured in energy (joules) divided by time. The SI unit of power is the watt (W) or joule per second (J/s).  Power is a scalar quantity, it has no direction. Horsepower is often used to describe the power delivered by a machine. Horsepower is a unit of power in the British system of measurement. It is the power required to lift 550 pounds by one foot in one second and is about 746 watts. The watt is often seen in relation to light bulbs. In this power rating, it is the rate at which the bulb converts electrical energy into light and heat. A bulb with a higher wattage will use more electricity per unit of time. If you know the power of a system, you can find the amount of work that will be produced, as WPt. If a bulb has a power rating of 50 watts, it will produce 50 joules per second. In an hour (3600 seconds) it will produce 180,000 joules. Work and Power When you walk a mile, your motive force is displacing your body, which is measured as the work is done. When you run the same mile, you are doing the same amount of work but in less time. The runner has a higher power rating than the walker, putting out more watts. A car with 80 horsepower can produce faster acceleration than a car with 40 horsepower. In the end, both cars are going 60 miles per hour, but the 80-hp engine can reach that speed faster. In the race between the tortoise and the hare, the hare had more power and accelerated faster, but the tortoise did the same work and covered the same distance in a much longer time. The tortoise showed less power. Average Power When discussing power, people are usually referring to average power, Pavg. It is the amount of work done in a period of time (ΔW/Δt) or the amount of energy transferred in a period of time (ΔE/Δt). Instantaneous Power What is the power at a specific time? When the unit of time approaches zero, calculus is needed to derive an answer, but it is approximated by force times speed.

Information Essay Example | Topics and Well Written Essays - 250 words

Information - Essay Example Another aspect of the black female writers’ problem is gender. As reiterated in yellow wallpaper, The American society in the context of the black community placed much pressure on women due to their gender and this considerably resulted to people overlooking their potential and even seriousness in their works as explained by the black literary scholars. The finally part of their hurdle is the idea of color. It is evident that most of the black-American female writers’ works was not particularly representative of the blacks. They were considered mere fiction without real life connection as they seemed to focus on the middle class and elite readers. The central theme of women oppression comes out in the yellow wallpaper as John seems to define everything that the narrator must do. Even when the narrator is sick, John is portrayed as a patriarch who is self-centered and takes little consideration of the narrator’s feeling due to her gender. The literary work on the yellow wallpaper is a reflection of the gender-based discrimination that women suffer every day in their efforts to disobey odds and express their ideas. Chapter five is a confirmatory test of the continued socio-economic challenges female artists, poets and novelists have to overcome. This can be supported by Alice Walker and Maya Angelou’s experiences with fictional writing in the female fraternity. Their assertions on the obstacles that continue to haunt women is clearly resonated by the narrator in the yellow