Tutor profile: Steven M.
Subject: Environmental Science
What is the basic economic benefits of using LED light bulbs in comparison to incandescent light bulbs?
LED's tend to last roughly 30,000 hours, while incandescent bulbs only last 1000. So realistically if you were to have a light on in your house after work from 5pm to 11pm (6 hours) the LED would last about 14 years while the incandescent will only last about 5-6 months. Additionally you pay for every kilowatt-hour of electricity used to power the bulb. For arguments sake lets say both the 60 watt incandescent and the 8 watt LED bulbs both produced 1000 lumens of light energy, which is not at all unrealistic. If we maintain that we keep the lights on 6 hours per day, the energy consumed for each bulb type over the course of a year would be as follows. 60W=0.06KW 0.06KW*6HR= 0.36KWH/Day 0.36KWH*365 Days= 131.4KWH/Year 8W=0.008KW 0.008KW*6HR=0.048KWH/Day 0.048KWH*365Days= 17.52KWH/Year If each kilowatt-hour of power cost $0.10 the incandescent bulb would cost $13.14 per year to power while the LED would cost $1.75 to power. This is caused by the efficiency of the bulbs. The incandescent bulb in this scenario is only producing 16.7 lumens of light energy per watt, while the LED is producing 125 lumens per watt. If an incandescent bulb costs $0.69 and an LED costs $1.50. In the time that it takes for the single $1.50 LED to burn out you would have spent roughly $19.32 on about 28 incandescent light bulbs. I hope you recycle your universal waste. : ) So if you factor together the cost of the bulb and energy of an LED light bulb compared to incandescent bulbs for a comparable time to the LED's lifespan the single LED bulb will cost $26 dollars over the course of 14 years. The Incandescent bulbs over the same length of time will cost $203.28 over 14 years. In one year's time the LED would cost $3.25 and the incandescent would cost $14.52 So LED's though maybe initially more expensive is significantly more economical. The reason this falls under the topic of environmental science is because by using a light bulb that is more efficient and longer lasting you consume less energy, produce less waste, and consume less materials. Therefore it is more environmentally friendly.
Subject: Political Science
What is the difference of freedom from and freedom to?
Freedom from would include freedoms such as freedom from starvation, freedom from religious persecution, and freedom from slavery. Freedom to would include the freedom to pursue a chosen profession, freedom to own guns, and freedom of mobility.
Subject: World History
What was the significance of the Battle of Hastings in 1066?
The Battle of Hastings, in which Norman forces from modern day France, led by William the Conqueror, invaded Saxon controlled England, is significant because it is often marked as the end of the Dark Ages in Europe and the start of the Medieval Period. Though this claim is disputed among historians, other contenders being the crusades and the rule of Charlemagne, This battle had a significant impact part of which is still felt today. The Norman forces were innovative in their attack, reviving the significant use of diverse unit types. At the time battles were commonly fought with a shield wall of spear-men. The Normans included archers and cavalry in their ranks giving them a significant advantage over their opponent. This is also believed to be the point at which such diversification of units began to be revived throughout Europe. Additionally, This battle allowed William to conquer and unite England under a stern Norman rule. These new Norman rulers spoke French, which created a linguistic and class-based divide in England which led to the introduction of many french words into the English language. From this new base in England the Normans would later invade and conquer Ireland and force the end of the Celtic Catholic faith in favor of Roman Catholicism. The Normans would rule over England until the death of King Stephen in 1154 and the French language was the primary language of the ruling class until Henry IV (1399-1413).
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