References




Comments

Post a Comment

Popular posts from this blog

First law of thermodynamics

Image
For a closed thermodynamic system, the first law of thermodynamics may be stated as: δ Q = d U + δ W {\displaystyle \delta Q=\mathrm {d} U+\delta W} , or equivalently, d U = δ Q − δ W , {\displaystyle \mathrm {d} U=\delta Q-\delta W,} where δ Q {\displaystyle \delta Q} is the quantity of energy added to the system by a heating process, δ W {\displaystyle \delta W} is the quantity of energy lost by the system due to work done by the system on its surroundings and d U {\displaystyle \mathrm {d} U} is the change in the internal energy of the system. The δ's before the heat and work terms are used to indicate that they describe an increment of energy which is to be interpreted somewhat differently than the d U {\displaystyle \mathrm {d} U} increment of internal energy (see Inexact differential). Work and heat refer to kinds of process which add or subtract energy to or from a system, while the internal energ...
Read more

History

Image
This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( November 2015 ) (Learn how and when to remove this template message) Ancient philosophers as far back as Thales of Miletus c. 550 BCE had inklings of the conservation of some underlying substance of which everything is made. However, there is no particular reason to identify their theories with what we know today as "mass-energy" (for example, Thales thought it was water). Empedocles (490–430 BCE) wrote that in his universal system, composed of four roots (earth, air, water, fire), "nothing comes to be or perishes"; instead, these elements suffer continual rearrangement. Epicurus (c. 350 BCE) on the other hand believed everything in the universe to be composed of indivisible units of matter - the ancient precursor to 'atoms' - and he too had some idea of the necessity of co...
Read more

47)Explained: What to expect on Republic Day 2021and what not to

India Republic Day -- Republic Day 2021: In 2020it was the agitation against the Citizenship Amendment Act (CAA). Nowthousands of farmersmostly from Punjab and Haryanahave been camping at the borders of Delhi for more than a couple of monthsdemanding the Centre repeal the three farm laws. To the second year in a stripRepublic Day celebrations inside national capital will be kept under the shadow of impetuous protests against laws approved by the Centre. In 2020it was the agitation against the Citizenship Amendment Act (CAA). This timethousands of farmersmostly from Punjab and Haryanahave been camping at the borders of Delhi for more than a couple of monthsdemanding the Centre repeal the three farm laws. This years Republic Day march will also be the first major public event in pandemic occasions. What is new this year The big event will be pared down in terms of the number of spectatorsthe size of marching contingents and other side attractions. The spectator size is reduced to 2500...
Read more