0

Guest

Courses New
Book a free demo of live class

Effective Grouping of Cells


The flow of current through a medium depends to a large extent on the effective grouping of cells. We first discuss some of the terms associated with this

Internal Resistance: As the name suggests, the resistance which is present in the interior of the circuit is called the internal resistance. It may also be defined as the resistance within the battery or any other voltage source which leads to a fall in the source of voltage whenever the current flows. 

External Resistance: Quite opposite to internal resistance is the concept of external resistance. The resistance which is not present internally, like not present in the battery is termed as external resistance.

Now we consider the type of grouping necessary for the current to be maximum:

For effective grouping, the current should be maximum. This implies that the value (mR + nr) should be minimum.

Now, mR + nr =   

The second term is non-zero, the term in the parenthesis 

(√mR - √nr)2 = 0.

Hence,  mR = nr

So  R = n / m r

Illustration:

There are 27 cells with an internal resistance 0.4 W and an external resistance 1.2 W. What is the most effective way of grouping them?

Solution:

Let there be n cells in series having m parallel branches

mn = 27                                    …… (1)

mR = nr                                    …… (2)

1.2 m = n (0.4)

3m = n                                  …… (3)

From equation (1) and (3), we get m = 3 and n = 9

askIITians offers comprehensive study material which covers the topic of grouping of cells in detail. It is important for the aspirants to master this topic in order to remain competitive in the JEE. the material covers all the topics of Physics of IIT JEE.
 

Related Resources

To read more, Buy study materials of Current Electricity comprising study notes, revision notes, video lectures, previous year solved questions etc. Also browse for more study materials on Physics here.


TOP Your EXAMS!

Upto 50% Scholarship on Live Classes

Course Features

  • Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Book a Live class Live courses Ask question
r