Answer:
651.
Step-by-step explanation:
Note: In the given series it should be -29 instead of 29 because 29 cannot be a term of AP whose first term is 91 and common difference is -6.
Consider the given series is
It is the sum of an AP. Here,
First term = 91
Common difference = 85 - 91 = -6
Last term = -29
nth term of an AP is
where, a is first term and d is common difference.
Sum of AP is
![Sum=\dfrac{n}{2}[\text{First term + Last term}]](https://tex.z-dn.net/?f=Sum%3D%5Cdfrac%7Bn%7D%7B2%7D%5B%5Ctext%7BFirst%20term%20%2B%20Last%20term%7D%5D)
![Sum=\dfrac{21}{2}[91+(-29)]](https://tex.z-dn.net/?f=Sum%3D%5Cdfrac%7B21%7D%7B2%7D%5B91%2B%28-29%29%5D)
![Sum=\dfrac{21}{2}[62]](https://tex.z-dn.net/?f=Sum%3D%5Cdfrac%7B21%7D%7B2%7D%5B62%5D)
Therefore, the sum of given series is 651.
5/6=0.83~
Meanwhile 3/4=0.75.
5/6 is bigger than 3/4.
Good luck!
Current density of solution a/m2 is given below
Step-by-step explanation:
Current density is the measure of current generated per unit surface area of electrode.
Eg: In microbial fuel cell/fuel cells, if you are using electrode with size of 5cm x 2cm and current produced is 200mA, then current density will be,
CD= Current/(projected area of electrode)
area of rectangle= LxB= 5cm x 2cm =10cm2
CD= 200mA/10cm2
CD= 20mA/cm2
Your Current will be 200mA.
Current density will be 20mA/cm2.
