# Questions Asked onFebruary 3, 2020

1. ## Physics

Silicon is doped with 2.0∗1016 arsenic atoms per cm3 . Assume an intrinsic carrier concentration equal to 1.7∗1010cm−3 at room temperature. What is the minority carrier concentration at room temperature ( T=300K ) in 104cm−3 ?

2. ## world history

Which plan proposed to maintain open trade between China and Western nations? Missionary Diplomacy Open Door policy National Sovereignty Salutary Neglect B?

3. ## Physics

Which of the dopant materials below can be used in order to achieve n-doping, considering Si as the bulk material? Ge In Ga As

4. ## Science

Calculate the number of atoms of chlorine present in 7.45g of KCL

5. ## Science

Consider a small module based on interconnected tandem cells of hydrogenated amorphous and microcrystalline silicon as depicted in the figure below. The Voc of a single tandem cell is 1.35V and the short-circuit density Jsc is 12mA/cm2. Which combination

6. ## Chemistry

The diffusion coefficient of electrons in silicon is De=36cm2s−1 . In a silicon layer, the electron density drops linearly from n=2.7∗1016cm−3 down to n=1015cm−3 over a distance of 2μm . What is the electron diffusion current density Jdiff,e (in

7. ## Math

Study the following diagram, where point C lies in the exterior of circle O. Segment WC is tangent to circle O at point W. CO¯¯¯¯¯¯¯¯, CW¯¯¯¯¯¯¯¯¯, and OW¯¯¯¯¯¯¯¯¯ are drawn in to create △OWC. If WC=15 and CO=17, what is OW?

8. ## Geography

According to the information in the chart for which are the following countries has the greatest amount of oil reserves

9. ## statistics

The random variable W can take on the values of 0, 1, 2, 3, or 4. The expected value of W is 2.8. Which of the following is the best interpretation of the expected value of random variable W? A. A randomly selected value of W must be equal to 2.8. B.The

10. ## math

Find the perimeter of the triangle whose vertices are the following specified points in the plane. (−9,−6),(−3,−6) and (9,−4)

11. ## Solar energy

The table below shows the total area, sun hours per day and energy consumption of five different countries: the United States, India, Brazil, Spain and the United Kingdom. Country Area ( km2 ) Sun hours per day Energy Consumption ( MWh/year ) United States

12. ## chemistry

Predict the rate of change in the concentration of N2O over this time interval. In other words, what is Δ[N2O]/Δt?

13. ## Math

solves 2x +3y=40, 5x +2y=34

14. ## chemistry

In the first 14.0 s of the reaction, 1.7×10−2 mol of O2 is produced in a reaction vessel with a volume of 0.340 L What is the average rate of the reaction over this time interval? 2 N2O(g) → 2 N2(g)+O2(g)

15. ## English

What would be a good topic for a compare and contrast essay? I need some ideas please!

16. ## Math

9^2y * 2^x = 72 Value of x and y

17. ## Social Studies

Which groups were considered citizens in ancient Greece? Select the three correct answers. A. aristocrats B. tenant farmers C. small farmers D. slaves E. foreigners F. women

asked by Brooklyn, I´m A Boy
18. ## math

could i get a step by step explanation for factoring this trinomial? i don't seem to understand how to get the final answer as i always get 2x(x+2)+x+2 2x^2+5x+2

19. ## Math

The area of the trapezoid student election sign is 5 square ft find two possible values for each base

20. ## Science

Which of the following statements is NOT true about solar inverters? A stand-alone inverter is supposed to work as an AC voltage source for a specified range of AC loads. An ideal grid-tied inverter has its operational voltage and frequency synchronized

21. ## chemistry

Attempt 2 If the density of solid iron is 7.87 g/cm 3 , what is the packing efficiency of Fe if it adopts a body‑centered cubic unit cell? The molar mass of Fe is 55.847 g/mol .

The supply and demand for a product are given by 2p − q = 100 and pq = 300 + 25q, respectively. Find the market equilibrium point.

23. ## Statistics

assuming that boys and girls are equally probable find the number of families out of 1600 each having 5 children with 3 boys,5 girls,2or3 boys and all children of the same sex.

24. ## Math

Segment WX is shown W•————————•X Explain how you would construct a perpendicular bisector of WX using a compass and a straightedge.

25. ## Geography

What is an informal statement expressing the commission's opinion on a public matter? A: petition B: law C: resolution D: formal statement I think it is d but I need help please?

26. ## poetry

What is the best paraphrase of these lines from “Stopping by Woods on a Snowy Evening”? The woods are lovely, dark, and deep, / But I have promises to keep A. I would like to stay, but I have too many other responsibilities. B. I made a promise that I

27. ## social studies

french settlers came to america for all the following reasons except

28. ## Science

1. Which of the following is true about photosynthesis? A) It is an exothermic reaction. B) It is an endothermic reaction.** C) It produces carbon dioxide. D) It occurs in animals. 2. Atomic theory is A) subject to change if new information is discovered.

29. ## Math

9. A relation contains the points (-5,-10) , (-2,-4), (-1,-2),(4,8), (5,10). Is this a function? Explain (2 points) Please help!

30. ## math

Three squirrels, Steve, Keith and Benjamin, have spent all day collecting nuts. At the end of the day they are very tired and go to bed. During the night, Steve wakes up and eats a nut. He then decides to take half of the remaining pile and hides it before

31. ## Science

Based on the following chemical equation how many molecules of Hydrogen (H) are present in the reactants side? 2H2 + O2 ----> 2H2O a. 1 b. 2 c. 3 d. 4

32. ## science

Which term would also correctly describe a scavenger? producer decomposer herbivores carnivore** i choose carnivore but i also think it can be decomposer

33. ## Math

Question text At the beginning of a race, a yacht crosses the start line and sails in a westerly direction at a speed of 6 m s-1. The current of the sea is flowing at 2 m s-1 towards the north-east. Calculate how farand in what direction (relative to

34. ## Civics

1.Under which circumstances might a u.s President send federal soldiers to enforce order in a state A. If a state needed help in collecting income tax. B. If a state's elected governor committed a crime C. If a states collected tolls on an interstate

35. ## geography

French settlers came to America for all the following reasons except: to convert Native Americans to Christ gold adventure furs

36. ## spanish

For the following paragraph, decide if the verb for each blank should be in preterite or imperfect. Cuando Marcos ___1___ (ser) joven, él ___2____ (querer) ser médico. La medicina le ____3_____ (interesar) mucho porque a él le ____4____ (gustar) ayudar

37. ## Physics

A uniform electric field of 775 N/C is produced within a particle accelerator. Starting from rest, what are the following? (a) the speed of an electron placed in this field after 25.4 ns have elapsed m/s (b) the speed of a proton placed in this field after

38. ## calculus

Expand 4/(x^2+4) as a power series centered at 0.

39. ## Science

Consider a crystalline PV module with the following output parameters mentioned at STC (Standard Test Conditions) conditions by the manufacturer. Pmax = 300 W Voc = 40 V Isc = 8 A NOCT = 40°C Temperature coefficient of power = -2 W/°C If the ambient

40. ## Chemistry

By means of ion/electron part equations, write fully balanced equations for the following reaction: the production of hydrogen by the action of hydrochloric acid on magnesium. I'm so confused as to why Cl, because it says hydrochloric acid, is not used as

The supply function for a product is 2p − q − 50 = 0, while the demand function for the same product is (p + 10)(q + 30) = 9600. Find the market equilibrium point.