This question is incomplete, the complete question is;
Calculate the value of ni for gallium arsenide (GaAs) at T = 300 K.
The constant B = 3.56×10¹⁴ (cm⁻³ K^-3/2) and the bandgap voltage E = 1.42eV.
Answer: the value of ni for gallium arsenide (GaAs) is 2.1837 × 10⁶ cm⁻³
Explanation:
Given that;
T = 300k
B = 3.56×10¹⁴ (cm⁻³ K^-3/2)
Eg = 1.42 eV
we know that, the value of Boltzmann constant k = 8.617×10⁻⁵ eV/K
so to find the ni for gallium arsenide;
ni = B×T^(3/2) e^ ( -Eg/2kT)
we substitute
ni = (3.56×10¹⁴)(300^3/2) e^ ( -1.42 / (2× 8.617×10⁻⁵ 300))
ni = (3.56×10¹⁴)(5196.1524)e^-27.4651
ni = (3.56×10¹⁴)(5196.1524)(1.1805×10⁻¹²)
ni = 2.1837 × 10⁶ cm⁻³
Therefore the value of ni for gallium arsenide (GaAs) is 2.1837 × 10⁶ cm⁻³
First, write down the information given and the change units if necessary (we must have similar units to operate on).
Initial speed, u = 36 km/h = 10 m/s
Final speed, v = 72 km/h = 20 m/s
Distance, s = 100 m
We know that
![{v}^{2} - {u}^{2} = 2as \\ {20}^{2} - {10}^{2} = 2 \times a \times 100 \\ 400 - 100 = 200 \times a \\ a = \frac{300}{200 } = \frac{3}{2} \: m {s}^{ - 2}](https://tex.z-dn.net/?f=%20%7Bv%7D%5E%7B2%7D%20%20-%20%20%7Bu%7D%5E%7B2%7D%20%20%3D%202as%20%5C%5C%20%20%7B20%7D%5E%7B2%7D%20%20-%20%20%7B10%7D%5E%7B2%7D%20%20%3D%202%20%5Ctimes%20a%20%5Ctimes%20100%20%5C%5C%20400%20-%20100%20%3D%20200%20%5Ctimes%20a%20%5C%5C%20a%20%3D%20%20%5Cfrac%7B300%7D%7B200%20%7D%20%20%3D%20%20%5Cfrac%7B3%7D%7B2%7D%20%20%5C%3A%20m%20%7Bs%7D%5E%7B%20-%202%7D%20)
Now, we substitute v, u, and a in the formula
![v = u + at \\ 20 = 10 + \frac{3}{2} t \\ \frac{3}{2} t = 10 \\ 3t = 20 \\ t = \frac{20}{3} = 6.67 \: seconds](https://tex.z-dn.net/?f=v%20%3D%20u%20%2B%20at%20%5C%5C%2020%20%3D%2010%20%2B%20%20%5Cfrac%7B3%7D%7B2%7D%20t%20%5C%5C%20%20%5Cfrac%7B3%7D%7B2%7D%20t%20%3D%2010%20%5C%5C%203t%20%3D%2020%20%5C%5C%20t%20%3D%20%20%5Cfrac%7B20%7D%7B3%7D%20%20%3D%206.67%20%5C%3A%20seconds)
Please mark Brainliest if this helps!
Answer:
# Program is written in python
# 22.1 Using the count method, find the number of occurrences of the character 's' in the string 'mississippi'.
# initializing string
Stringtocheck = "mississippi"
# using count() to get count of s
counter = Stringtocheck.count('s')
# printing result
print ("Count of s is : " + str(counter))
# 2.2 In the string 'mississippi', replace all occurrences of the substring 'iss' with 'ox
# Here, we'll make use of replace() method
# Prints the string by replacing iss by ox
print(Stringtocheck.replace("iss", "ox"))
#2.3 Find the index of the first occurrence of 'p' in 'mississippi'
# declare substring
substring = 'p'
# Find index
index = Stringtocheck.find(substring)
# Print index
print(index)
# End of program
Answer:
![18 ft^{2}](https://tex.z-dn.net/?f=18%20ft%5E%7B2%7D)
Explanation:
Soil bearing pressure=![\frac {Load}{Area}](https://tex.z-dn.net/?f=%5Cfrac%20%7BLoad%7D%7BArea%7D)
Since we're given pressure of 2500 psf and load of 45000 pounds
The area=![\frac {45000}{2500}=18](https://tex.z-dn.net/?f=%5Cfrac%20%7B45000%7D%7B2500%7D%3D18)
Therefore, the smallest area of safe footings should not be less than ![18 ft^{2}](https://tex.z-dn.net/?f=18%20ft%5E%7B2%7D)