The electron to move a distance of 1 micron is approximately 0.255 s.
The main equation describing the evolution of the probability Pm (t) of finding an electron at point m in a molecular chain with lattice constant a = 1 nm is given by the formula: dt = -2RP.m RPm 1 RPm- 1 Assuming that R = 10-125 , calculate the diffusion constant in units of cm²/s. The diffusion constant is given by D = a²v/2t where a = 1 nm, v = RPm = 2RP and R = 10-125D = a²v/2tD = (10-9)² x 2RP / 2t = 4.2 x 10 ⁻¹⁰ RPt
Evaluate the characteristic time for an electron to travel a distance of 1 micron. Room temperature can be assumed for the electron, T = 27°C = 300K. The diffusion constant is given by the formula D = kbT/6πηra = (1.38 x 10-23 J/K) (300K) / (6π(8.9 x 10-4) Nsm-² x 1 x 10-⁷ m)D = 1 .57 x 10-2 cm²/s Distance 1 micron = 10⁻⁴ cm So by the formula D = sqrt((2d²)/t) t = 2d²/Dt = 2 x (10⁻⁴)² / (1.57 x 10 ⁻⁵ ) = 0.255 s Therefore, the characteristic time of an electron to travel a distance of 1 micron is approximately 0.255 s.
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The proportion of supermarket customers who do not buy store-brand products is to be estimated. Suppose 500 customers are selected from the roughly 20,000 customers who shop at the stores citywide. The sample proportion of supermarket customers who do not buy store-brand products equals 33.5%. Which value(s) can be labeled as statistic(s)?
Options :
A.
33.5%
B.
20,000 and 33.5%
C.
500 and 20,000
D.
20,000
Answer:
A.) 33.5%
Step-by-step explanation:
A statistic value is simply a numerical statistical estimate or value which is obtained from the sample data or value. Here the statistic is the statistical value which is obtained the sample of 500 customers selected from the about 20000 population value 500 itself is the sample size while 33.5% is the sample. Proportion of supermarket customers who do not buy store-brand products.
20,000 = population size ;
500 = sample. Size
33.5% =. Statistic
This is confusing can you help? NO LINKS!!!
Answer:
huh?
Step-by-step explanation:
did you forget a pic?
Answer:
whatdo u need help with love?
Step-by-step explanation:
Please help I’m having a hard time :(
Answer:
i think you're right- you seem to have all numbers squared correctly, also every negative value squared becomes a positive number, which means that your answers are correct.. what is your issue?
Step-by-step explanation:
A rectangular prism has a volume of 900 cubic units. The prism has a length of 25 units and a width of 12 units. Which equation could be used to find h, the height of the prism?
Answer:
52 cubic units
Step-by-step explanation:
got it right on edg
Answer:
37h 900
Step-by-step explanation:
Which of the following describes the square root of 41. 5,6 6,7 20,21 40,42
Answer:
6,7
Step-by-step explanation:
the squre root of 41 is 6.403
1 point
Finish the similarity statement. (Note: your answer will be the 3 letters of
the other triangle. You must place them in the correct order and use
CAPITAL letters!) APQR-4
R
4 in
6 in
VA
8 in
4 in
3 in
2 in
YOUR ANSWER IS ANGLE BAC
help a girl out? please
Answer:
21/20
Step-by-step explanation:
PLEASE HELP ILL GIVE BRAINLIEST
WHATS THE PERCENT CHANGE SHOW WORK
Answer:
34.55556%
Step-by-step explanation:
Evaluate the expression when b=4 and x=-2 .
b-4x
Answer:
12
Step-by-step explanation:
b-4x
Plug in 4 as b and -2 as x
= (4)-4(-2)
Multiply 4 and 2
= 4-(-8)
Two negatives make a positive
= 4+8
= 12
I hope this helps!
as with simple linear regression, we desire the residuals to (select all that apply)
In simple linear regression, we desire the residuals to have certain characteristics. Specifically, we want the residuals to be:
Random: The residuals should not follow a specific pattern or exhibit any systematic behavior. Random residuals indicate that the model captures the underlying relationship between the variables adequately.
1. Normally distributed: The residuals should follow a normal distribution. This assumption allows for the use of statistical inference and hypothesis testing techniques based on normality.
2. Zero mean: The average of the residuals should be close to zero. A zero mean indicates that, on average, the model is not biased and accurately represents the data.
3. Homoscedastic: The residuals should have constant variance across all levels of the independent variable. Homoscedasticity ensures that the model's performance is consistent throughout the range of values.
By satisfying these criteria, we can ensure that the model is valid, reliable, and provides accurate predictions.
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Find m∠P. explanation is optional
The water used by the 12 students during the experiment was poured from a beaker after the water was poured 1/4 gallon of water was left in the beaker What was the total number of fluid ounces of water in the beaker before the water was poured by the 12 students
Answer:
128 fluid ounces
Step-by-step explanation:
We were told that:
During the experiment was poured from a beaker after the water was poured 1/4 gallon of water was left in the beaker
Hence, this means that the total gallon of water in the beaker is 1 gallon
Convert 1 gallon to fluid ounces
1 gallon =128 fluid ounces
Therefore, the total number of fluid ounces of water in the beaker before the water was poured by the 12 students is 128 fluid ounces.
I’m sorry for the spam questions but I need help
Answer:
x = 30
Step-by-step explanation:
2x + x = 90
3x = 90
x = 30
HELP ASAP, due today.
Answer:
(A) B h(x)= -2x-5.5
(B) The y intercept is (0,-5.5)
(C) The rate of change is -2
(D) The x intercept is (-2.75,0)
Please help I’ll give brainliest
Answer:
c
Step-by-step explanation:
Answer:
c
Step-by-step explanation:
Consider the circular annulus (a plane figure consisting of the area between a pair of concentric circles) specified by the range: 1 1 cases. b) Find the potential that satisfies the following boundary conditions 1 u (1,0) = sin? (0) ), u (2,0) = 0. ) = + (1 - cos (20),
The potential that satisfies the given boundary conditions in part (a) and (b) is: [tex]\[u(r, \theta) = \sin(\theta)\][/tex] and [tex]\[u(r, \theta) = \sin(\theta)\][/tex] respectively.
Consider the circular annulus (a plane figure consisting of the area between a pair of concentric circles) specified by the range:
[tex]$1 \leq r \leq 2$.[/tex]
a) Find the potential that satisfies the following boundary conditions:
[tex]\[\begin{aligned}u(1,0) &= \sin(\theta) \\u(2,0) &= 0 \\u(\theta, 1) &= 1 + (1 - \cos(2\theta))\end{aligned}\][/tex]
b) Find the potential that satisfies the following boundary conditions:
[tex]\[\begin{aligned}u(1,0) &= \sin(\theta) \\u(2,0) &= 0 \\u(\theta, 1) &= 1 + (1 - \cos(20\theta))\end{aligned}\][/tex]
To solve this problem, we can use separation of variables and assume a solution of the form:
[tex]\[u(r, \theta) = R(r)\Theta(\theta)\][/tex]
Plugging this into Laplace's equation [tex]$\nabla^2u = 0$[/tex] and separating variables, we get:
[tex]\[\frac{1}{R}\frac{d}{dr}\left(r\frac{dR}{dr}\right) + \frac{1}{\Theta}\frac{d^2\Theta}{d\theta^2} = 0\][/tex]
Solving the radial equation gives us two solutions:
[tex]\[R(r) = A\ln(r) + B\quad \text{and} \quadR(r) = C\frac{1}{r}\][/tex]
For the angular equation, we have:
[tex]\[\Theta''(\theta) + \lambda\Theta(\theta) = 0\][/tex]
The general solution to this equation is given by:
[tex]\[\Theta(\theta) = D\cos(\sqrt{\lambda}\theta) + E\sin(\sqrt{\lambda}\theta)\][/tex]
To satisfy the boundary conditions, we can impose the following restrictions on [tex]$\lambda$[/tex] and choose appropriate constants:
For part (a)
[tex]\[\begin{aligned}R(1) &= 0 \implies B = -A\ln(1) = 0 \implies B = 0 \\R(2) &= 0 \implies A\ln(2) + B = 0 \implies A\ln(2) = 0 \implies A = 0 \\\Theta(0) &= \sin(0) \implies D = 0 \\\Theta(0) &= \sin(0) \implies E = 1\end{aligned}\][/tex]
Therefore, the potential that satisfies the given boundary conditions in part (a) is:
[tex]\[u(r, \theta) = \sin(\theta)\][/tex]
For part (b)
[tex]\[\begin{aligned}R(1) &= 0 \implies B = -A\ln(1) = 0 \implies B = 0 \\R(2) &= 0 \implies A\ln(2) + B = 0 \implies A\ln(2) = 0 \implies A = 0 \\\Theta(0) &= \sin(0) \implies D = 0 \\\Theta(0) &= \sin(0) \implies E = 1\end{aligned}\][/tex]
Therefore, the potential that satisfies the given boundary conditions in part (b) is:
[tex]\[u(r, \theta) = \sin(\theta)\][/tex]
Please note that in both parts (a) and (b), the radial solution does not contribute to the potential due to the boundary conditions at r=1 and r=2. Thus, the solution is purely dependent on the angular part.
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helppppppppppppppppp
Answer:
32.2-32.61Step-by-step explanation:
define a scheme procedure, named (heap-insert f x h), which adds element x to heap h using the first-order relation f to determine which element belongs at the root of each (sub)tree.
The scheme procedure "heap-insert" adds an element x to a heap h using the first-order relation f to determine the root element in each subtree.
The "heap-insert" procedure can be defined as follows in Scheme:
(define (heap-insert f x h)
(cond
((null? h) (list x))
((f x (car h)) (cons x h))
(else (cons (car h) (heap-insert f x (cdr h))))))
This procedure takes three arguments: f, x, and h. The first argument f is a first-order relation that determines the ordering of elements in the heap. The second argument x is the element to be inserted into the heap. The third argument h is the existing heap.
The procedure first checks if the heap h is empty. If it is, it simply creates a new heap with x as the only element. If the heap is not empty, it compares x with the root element (car h) using the relation f. If f determines that x should be the new root element, it adds x to the heap by consing x with h. Otherwise, it recursively calls the heap-insert procedure on the remaining elements (cdr h) until it finds the appropriate position to insert x.
In this way, the "heap-insert" procedure ensures that the new element x is inserted into the heap h while maintaining the heap property defined by the relation f.
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PLEASE SOMEONE HELLPPP i actually need it
Decide whether the composite functions, fog and g • f, are equal to x. f(x) = *25, g(x) = 2x - 5 2 O No, no O Yes, yes Yes, no O No, yes
The composite functions fog and g • f are not equal to x. The function fog simplifies to 4x² - 20x + 25, while g • f simplifies to 45. Therefore, neither composite function equals x.
To determine whether the composite functions fog and g • f are equal to x, we need to evaluate each expression separately and compare the results.
1. fog (or f(g(x))):
f(g(x)) = f(2x - 5)
To compute f(2x - 5), we substitute (2x - 5) into the function f(x) = x²:
f(2x - 5) = (2x - 5)²
Expanding this expression, we get:
f(2x - 5) = 4x² - 20x + 25
Therefore, fog is not equal to x since f(2x - 5) simplifies to 4x² - 20x + 25, not x.
2. g • f (or g(f(x))):
g(f(x)) = g(25)
To compute g(25), we substitute 25 into the function g(x) = 2x - 5:
g(25) = 2(25) - 5
g(25) = 50 - 5
g(25) = 45
Therefore, g • f is not equal to x since g(25) evaluates to 45, not x.
In conclusion, neither fog nor g • f is equal to x. The composite functions do not simplify to x; fog simplifies to 4x²- 20x + 25, and g • f simplifies to 45.
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Question 3 of 10
Which of the following are exterior angles? Check all that apply.
6
DA. 26
B. 24
C. 23
OD. 22
OE. Z1
O F. 25
Answer:
I believe the answer to be 5 and 4
The exterior angles of the given triangle are angles 4 and 5
What is triangle?A triangle is a polygon with three sides, angles and vertices.
Given that, a triangle, with angles, 1, 2, 3, 4, 5 we need to find the exterior angles,
An exterior angle of a polygon is the angle that lies outsides of the polygon,
Here, we can see, that only two angles 4 and 5 lies outsides of the triangles
Therefore, the exterior angles are 4 and 5
Hence, the exterior angles of the given triangle are angles 4 and 5
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The price of n tickets to a concert is 8n + 9 dollars. What is the cost in dollars for 7 tickets to the concert
Answer: 65
Step-by-step explanation:
8nn+7 is your given expression. Plug in 7 for n, the number of tickets: 8(7)+9=56+9=65
PLEASE HELP ME!!!! In each diagram AB is tangent to C at B. Find the value of x.
What is the value of "w" ?
Answer:
w = [tex]\sqrt{147}[/tex]
Step-by-step explanation:
Using Pythagoras' identity in the right triangle
w² + 7² = 14²
w² + 49 = 196 ( subtract 49 from both sides )
w² = 147 ( take the square root of both sides )
w = [tex]\sqrt{147}[/tex]
What is the solution to the equation fraction 4 over 5 n minus fraction 3 over 5 equals fraction 1 over 5 n? (1 point)
Answer:
n= 1
Got it right on my test \(￣︶￣*\))
Does the equation 3(2x−1)+5=6(x+1) have one, none, or an infinite amount of solutions?
Answer: No solutions
Step-by-step explanation: If you solve the problem all the way, you get 0 = 4 which is not valid so there is simply no solution
The given equation 3(2x−1)+5=6(x+1) has no solution. Option B is correct.
What is simplification?The process in mathematics to operate and interpret the function to make the function or expression simple or more understandable is called simplifying and the process is called simplification.
Here,
Given equation ⇒
⇒= 3(2x−1)+5=6(x+1)
Simplify the above expression,
⇒ 6x - 3 + 5 = 6x + 1
⇒ 2 ≠ 1
Thus, the given equation has no solution.
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The center is (3,-2), and a point in the circle is (23, 19)
Answer:
Circumference is about 182.21
Step-by-step explanation:
Use the distance formula to find the radius of the circle with the two coordinates given. The radius of this circle is 29. Plug 29 into the formula 2(pi)r to find the Circumference. The answer is 182.21
The equation of the circle is [tex]\rm(x-3)^2+(y+2)^2=29^2[/tex].
What is the equation of circle?The equation of the circle is given by;
[tex]\rm (x-h)^2+(y-k)^2=r^2[/tex]
Where r is the radius and h and k are the centre of the circel.
The radius of the circle is;
[tex]r=\sqrt{(23-3)^2+(19-(-2))^2} \\\\r=\sqrt{(20)^2+(21)^2} \\\\r=\sqrt{400+441}\\\\r =\sqrt{841}\\\\r=29[/tex]
The equation of the circle is;
[tex]\rm (x-h)^2+(y-k)^2=r^2\\\\\rm (x-3)^2+(y-(-2))^2=29^2\\\\ (x-3)^2+(y+2)^2=29^2[/tex]
Hence, the equation of the circle is [tex]\rm(x-3)^2+(y+2)^2=29^2[/tex].
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What should be done to both sides of the equation in order to solve y - 4.5 = 12.2?
To solve the equation y - 4.5 = 12.2 we have to add 4.5 on both sides of the equation.
What is Equation?Two or more expressions with an Equal sign is called as Equation.
The given equation is y - 4.5 = 12.2
y minus four point five equal to twelve point two.
In the equation y is the variable and minus is the operator in the equation.
To solve the equation we have to isolate the variable y.
To isolate the variable y we have to add 4.5 on both sides of the equation
y-4.5+4.5=12.2+4.5
y=16.7
Hence, to solve the equation y - 4.5 = 12.2 we have to add 4.5 on both sides of the equation.
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please help
If 2500 square feet of grass supplies enough oxygen for a
family of four, how much grass is needed to supply oxygen for a family
of five?
Answer:
3125
Step-by-step explanation:
first, find the unit rate.
2500/4=625
625= amount of oxygen needed to supply a family of one(or just one single person)
625*5=3125
***with these problems, always try to find the unit rate first which is the amount of something per one unit. it'll be helpful to solve the questions following it.
approximate the area under the curve graphed below from x = 2 x=2 to x = 5 x=5 using a left endpoint approximation with 3 subdivisions.
The approximate area under the curve from x = 2 to x = 5, using a left endpoint approximation with 3 subdivisions, is 13.5 square units.
To approximate the area under the curve, we divide the interval from x = 2 to x = 5 into three equal subdivisions, each with a width of (5 - 2) / 3 = 1. The left endpoint approximation involves using the leftmost point of each subdivision to approximate the height of the curve.
In this case, we evaluate the function at x = 2, x = 3, and x = 4, and use these values as the heights of the rectangles. The width of each rectangle is 1, so the areas of the rectangles are calculated as follows:
Rectangle 1: Height = f(2) = 2, Area = 1 * 2 = 2 square units.
Rectangle 2: Height = f(3) = 4, Area = 1 * 4 = 4 square units.
Rectangle 3: Height = f(4) = 7, Area = 1 * 7 = 7 square units.
Finally, we add up the areas of the three rectangles to obtain the approximate area under the curve: 2 + 4 + 7 = 13 square units. Therefore, the approximate area under the curve from x = 2 to x = 5 using a left endpoint approximation with 3 subdivisions is 13.5 square units.
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