Wikipedia:Reference desk/Archives/Science/2021 October 8

= October 8 =

Why there is no "t" in this power formulae?
By definition, It is equal to the amount of work done divided by the time it takes to do the work. But in P= VI, I don't see "t" here. Why there is no "t" in this power formulae? Rizosome (talk) 02:52, 8 October 2021 (UTC)
 * Because the I is electric current, which is defined as the amount of electric charge moved divided by the time taken: I = Q/t. --184.144.99.72 (talk) 04:04, 8 October 2021 (UTC)


 * Rizosome, these are things you can easily find out yourself if you spend a little time researching the topic. Our article on electric power has a section that shows the following formula:
 * $$P = \text{work done per unit time} = \frac{W}{t} = \frac{W}{Q} \frac{Q}{t} = VI \,$$
 * which explains how the $$t$$ "disappears". --Lambiam 07:02, 8 October 2021 (UTC)
 * Not really. It doesn't explain how V and I are related to W, Q and t. --  Jack of Oz   [pleasantries]  19:39, 8 October 2021 (UTC)
 * W/Q = V, Q/t = I. That's what the equation means.  -- Jayron 32 10:56, 12 October 2021 (UTC)
 * Sorry for being obtuse, but that seems to be missing a step. One must already know that W/Q = V and Q/t = I, in order to arrive at the outcome. But that's not stated or explained in the article. --  Jack of Oz   [pleasantries]  22:00, 12 October 2021 (UTC)

Ancestry genetics history of Turkmens & Circassians
Greetings,

Non–elite women's slavery in Ottoman Turkey has been one of my focus area of writing on WP. Turkish slavery was much different to Atlantic slavery. Ottoman Turkish slavery had high rates import and usage of slaves for domestic and war activities, manumission and social absorption of slaves.

This would have transformed Turkish genetic pool since pre−modern times. Present WP articles Turkmens and Circassians do not seem to offer any info on Ancestry genetics history of Turkmens & Circassians. But I suppose that must have been researched reasonably by now.

I came across articles Prehistoric Caucasus & Y-DNA haplogroups in populations of the Caucasus But for lay readers like me understanding Turkish & Circassian genetic pool and transformation in them since pre−modern times remains difficult.

From which end to start entangling these questions, can any sources be suggested?

&#32;Bookku, &#39;Encyclopedias &#61; expanding information &#38; knowledge&#39; (talk) 05:06, 8 October 2021 (UTC)


 * Setting effects of slave imports apart, there are two competing theories about the dominant genetic origins of modern Turks. One is that they are mainly the descendants of the Oghuz clans (Turkmens) that settled in Anatolia after the Seljuk victory over the Byzantine Empire in 1071 in the Battle of Manzikert. The other is that they are mainly the descendants of the Anatolian population at the time, undergoing a gradual process of cultural Turkification. The first theory is mainly adhered to by Turkish nationalists who prefer to portray themselves as the descendants of glorious victors. It is not supported by the historical record, which does not indicate an unprecedented mass emigration or mass genocide of Anatolians in the late Middle Ages. Genetic studies of the present-day Anatolian population also showed a relatively low admixture of haplogroups of Central Asian origin. I don't have references ready, but if memory serves these studies were led by Cavalli-Sforza. I don't know if there is a basis for assuming a considerable and identifiable distinction between the 11th century Anatolian gene pool and that of the Caucasian (in the geographic sense) populations in the following centuries. --Lambiam 06:53, 8 October 2021 (UTC)
 * We have an article on Genetic studies on Turkish people. --Lambiam 07:04, 8 October 2021 (UTC)

Six bulbs of 60W each
9. In a house there are six bulbs of 60 W each six of 40 Weach, and three of 11W each. All of them are used for 4 hours a day. How many units of electricity will be used up in 30 days? How much will they have to pay at 2.80 rupees per unit? — Preceding unsigned comment added by 106.220.124.171 (talk) 11:36, 8 October 2021 (UTC)
 * Is this a story problem from your school? ←Baseball Bugs What's up, Doc? carrots→ 11:55, 8 October 2021 (UTC)
 * Does look rather like a test question; suggest your answer should be: "There is insufficient information provided to answer this question; specifically a 'unit' would need to be defined." Chris (talk) 12:48, 8 October 2021 (UTC)
 * If by "unit" they mean "watt", it's very basic arithmetic which the OP should be able to figure out. The OP could read Kilowatt-hour for further understanding. ←Baseball Bugs What's up, Doc? carrots→ 12:50, 8 October 2021 (UTC)
 * Agreed, a unit is almost certainly kWh (but that should have been specified in the question). Never mind, Let's see whether the OP is prepared to do a little work? First problem - how many hours is each bulb used for over the 30 day period at 4 hours per day? Chris (talk) 12:58, 8 October 2021 (UTC)
 * [Edit Conflict] In the UK and probably also in India (being a Commonwealth country that inherited British usage), "Unit" (originally "Board of Trade Unit") is a synonym for "Kilowatt-hour", frequently used by electricity providers on utility bills. This is probably sufficiently well known (or taught) that in the context of an academic test no definition should be required (and the definition may in a live test be provided along with others as an addendum to the test paper).
 * If the OP reads the article sub-section Kilowatt-hour, they will see example calculations that will show them how to calculate the answer that they require. {The poster formerly known as 87.81.230.195} 90.193.131.207 (talk) 13:08, 8 October 2021 (UTC)
 * Wiktionary gives "(Britain, electricity) One kilowatt-hour (as recorded on an electricity meter)" as sense 17 of unit. And our article kilowatt-hour states:
 * The Board of Trade unit (BOTU) is an obsolete UK synonym for kilowatt-hour. The term derives from the name of the Board of Trade which regulated the electricity industry until 1942 when the Ministry of Power took over.
 * In India, the kilowatt-hour is often simply called a Unit of energy. A million units, designated MU, is a gigawatt-hour and a BU (billion units) is a terawatt-hour.
 * So I take it that in the UK the obsolete synonym BOTU lives on as simply unit. Is this term only used colloquially, or also found in communications from the energy companies to their customers? --Lambiam 05:21, 9 October 2021 (UTC)
 * On my bills it is not used as a billing quantity - my bills still say kWH. But a note on the bill defines a kWH and then explains that it is also called a 'unit'.--Phil Holmes (talk) 09:31, 9 October 2021 (UTC)
 * I don't know what a "BOTU" is. Board of Trade Unit is abbreviated BTU. There is an obsolete unit called the British Thermal Unit (approximately 0.000293071 kWh), which is abbreviated Btu, or BThU, or sometimes BTU, and which may confuse Americans. DuncanHill (talk) 14:16, 9 October 2021 (UTC)
 * I just copy-and-pasted the sentence from the article, but here are some uses of the initialism:, , , . The texts in which this is found are older US trade publications or contemporary Indian textbooks. The Btu may be obsolete in the UK, but in the US it is the customary unit for specifying the capacity of a residential heating system. --Lambiam 15:23, 9 October 2021 (UTC)
 * Yes, this is no doubtedly a school problem. Notice there is a 9 at the front, which means problem #9. Original-poster was apparently slow to remove that. But I don't know what wheach means. 67.165.185.178 (talk) 11:51, 9 October 2021 (UTC).
 * It's obviously missing a space, and should have read ". . . 40 W each, . . ." {The poster formerly known as 87.981.230.195} 90.193.131.207 (talk) 18:16, 9 October 2021 (UTC)