1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Zepler [3.9K]
3 years ago
14

A. Calculate the diffusion coefficient for magnesium in aluminum at 450°C.

Computers and Technology
1 answer:
SIZIF [17.4K]3 years ago
5 0

Answer:

a) D = 4.88 * 10^(-14) m^2 / s

b)   <em>t </em>= 1.1 hr

Solution:

a) Magnesium in Aluminum diffusion:

D = Do * exp(-Qd / RT)

  =  (1.2 * 10^(-4) m^2 / s) * exp ( - 130,000 / 8.31 * 723.15)

  = 4.88 * 10^(-14) m^2 / s

D = 4.88 * 10^(-14) m^2 / s

b) The composition remains same at say the distance Xo:

(Cx - Co) / (Cs - Co) = Constant

Xo^2 / D_{550} * <em>t </em>= Xo^2 / D_{450} * 15

D_{550} * <em>t </em>= D_{450} * 15

(1.2 * 10^(-4) m^2 / s) * exp ( - 130,000 / 8.31 * 723.15) * <em>t</em>

(4.88 * 10^(-14) m^2 / s) * 15

by, solving for <em>t </em>we get:

 <em>t </em>= 1.1 hr

So, the time required is 1.1 hr.

You might be interested in
Write a loop that continually asks the user what pets the user has until the user enters rock in which case the loop ends. It sh
mote1985 [20]

Loops are program statements that are repeated as long as the loop condition is true.

The loop in Python, where comments are used to explain each line is as follows:

#This initializes the number of pets to 0

count = 0

#This gets input for the pet name

pet = input("Pet: ")

#This is repeated until the user enters "rock"

while pet.lower() != "rock":

   #This increases the number of pets by 1

   count+=1

   #This prints the pet and the number of pets

   print("You have a",pet,"with a total of",str(count),"pet(s)")

   #This gets input for the pet name

   pet = input("Pet: ")

Read more about loops at:

brainly.com/question/19344465

6 0
2 years ago
Write a recursive method that tests whether a string is a palindrome. It should return a boolean T or F depending on whether or
Sveta_85 [38]

Answer:

// program in java.

// library

import java.util.*;

// class definition

class Main

{

// recursive function to check palindrome

   public static boolean isPalin(String str){

// base case

     if(str.length() == 0 ||str.length()==1){

        return true;

     }

// if first character is equal to last

     if(str.charAt(0) == str.charAt(str.length()-1))

     {

     // recursive call

        return isPalin(str.substring(1, str.length()-1));

     }

     // return

     return false;

  }

  // main method of the class

public static void main (String[] args) throws java.lang.Exception

{

   try{

    // object to read input

Scanner scr=new Scanner(System.in);

System.out.print("Enter a string:");

 // read string from user

String myString =scr.nextLine();

 // call function to check palindrome

     if (isPalin(myString)){

        System.out.println("Given String is a palindrome");

     }

// if string is not palindrome

     else{

        System.out.println("Given String is not a palindrome");

     }    

   }catch(Exception ex){

       return;}

}

}

Explanation:

Read a string from user and assign it to variable "myString" with scanner object. Call the method isPalindrome() with string input parameter.In this method, if  length of string is 0 or 1 then it will return true(base case) otherwise it will call itself and compare first character with last character.If string is palindrome then function will return true else return false.

Output:

Enter a string:ababa                                                                                                      

Given String is a palindrome

8 0
4 years ago
4. Write a program which selects two integer numbers randomly, adds the numbers and asks the user to enter the answer and then c
KIM [24]

Answer:

import random

number1 = random.randrange(0, 1000)

number2 = random.randrange(0, 1000)

answer = int(input("Enter a number: "))

if answer == number1 + number2:

   print("Your answer is correct")

else:

   print("Your answer is not correct")

Explanation:

The code is in Python

Create two integer numbers using random

Ask the user for an input

Check if answer is equal to number1 + number2. If they are equal, print "answer is correct". Otherwise, print "answer is not correct".

7 0
3 years ago
How will you maintain electrical tools and equipment?
PSYCHO15rus [73]
Electronic tools should not rub against each other when stored. Keep all the tools in the dry area and protect them from moisture, dust, and direct sunlight. To prevent injuries, keep the sharpen tool in a tool holder.
4 0
3 years ago
Read 2 more answers
Deon would like to add a lot of color to a web page for a local accounting office even though they are a very conservative offic
Neko [114]
The colors should match the attitude the business would like to present.
4 0
3 years ago
Other questions:
  • The keyboard, mouse, trackpad, microphone, light pen, and voice recognition are examples of _____ devices.
    5·1 answer
  • Write a program that prompts the user to enter a three digit integer and determine whether it is a palindrome number.
    12·1 answer
  • Ron is the IT director at a medium-sized company and is constantly bombarded by requests from users who want to select customize
    5·1 answer
  • After installation of SSL certificate website asking for username and password.
    6·1 answer
  • WHAT is the USE OF RIBBON TAB​
    10·1 answer
  • Physical activity such as sports or even a brisk walk can help reduce
    7·2 answers
  • A quien se le conoce como el padre de la tecnologia?
    10·1 answer
  • The router is physically located in a server room that requires an ID card to gain access. You've backed up the router configura
    8·1 answer
  • Write a program to enter a number and test if it is greater than 45.6. If the number entered is greater than 45.6, the program n
    8·1 answer
  • which two host names follow the guidelines for naming conventions on cisco ios devices? (choose two.)
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!