Click to Chat
1800-2000-838
+91-120-4616500
CART 0
Use Coupon: CART20 and get 20% off on all online Study Material
Welcome User
OR
LOGIN
Complete Your Registration (Step 2 of 2 )
Grouping of Identical Cells Series Grouping E.m.f. of the cell is e and internal resistance is r. Alt txt: series grouping Applying Kirchhoff’s Law e– ir + e– ir +… (to n times) – iR = 0 Þ i = nz / R + nr = ε / (R/n) + r Illustration: In a series grouping of N cells, current in the external circuit is l. The polarity of how many cells should be reversed so that the current becomes (1/3)rd of the earlier value? Solution: Before reversing the polarity of the cells, the current is l = NE / R + Nr Let n cells be reversed in their polarity. \ Net emf = (N – n)E – nE = (N – 2n) E Total resistance NR + R Þ i’ = (N – 2n)E / Nr + R But, 1' / 1 = (N–2n)E / (R + Nr) / (NE / Nr + R) = N – 2n / N Þ n = N/3, This is valid only when N is a multiple of 3, otherwise it cannot be done. Parallel Grouping Let there be n identical rows each containing a cell of emf e and a resistance r arranged as shown in the figure. Alt txt : parallel grouping Applying Kirchhoff’s law e–1/ n r – lR = 0 Þ l = nz / r + nR * To get maximum current, cells must be connected in series if effective internal resistance is less than external resistance and in parallel if effective internal resistance is greater than external resistance. Mixed Grouping Let emf of each cell is e and internal resistance is r. Number of rows is m and number of cells in each row is n Alt txt : mixed-grouping Applying Kirchhoff’s law, ne– n1/m r – lR = 0 Þ l = mnz / mR + nr 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.
E.m.f. of the cell is e and internal resistance is r.
Alt txt: series grouping
Applying Kirchhoff’s Law
e– ir + e– ir +… (to n times) – iR = 0
Þ i = nz / R + nr = ε / (R/n) + r
Illustration:
In a series grouping of N cells, current in the external circuit is l. The polarity of how many cells should be reversed so that the current becomes (1/3)rd of the earlier value?
Solution:
Before reversing the polarity of the cells, the current is
l = NE / R + Nr
Let n cells be reversed in their polarity.
\ Net emf = (N – n)E – nE = (N – 2n) E
Total resistance NR + R
Þ i’ = (N – 2n)E / Nr + R
But, 1' / 1 = (N–2n)E / (R + Nr) / (NE / Nr + R) = N – 2n / N
Þ n = N/3, This is valid only when N is a multiple of 3, otherwise it cannot be done.
Let there be n identical rows each containing a cell of emf e
and a resistance r arranged as shown in the figure.
Alt txt : parallel grouping
Applying Kirchhoff’s law
e–1/ n r – lR = 0 Þ l = nz / r + nR
* To get maximum current, cells must be connected in series if effective internal resistance is less than external resistance and in parallel if effective internal resistance is greater than external resistance.
Let emf of each cell is e
and internal resistance is r.
Number of rows is m and number of cells in each row is n
Alt txt : mixed-grouping
Applying Kirchhoff’s law,
ne– n1/m r – lR = 0
Þ l = mnz / mR + nr
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.
Signing up with Facebook allows you to connect with friends and classmates already using askIItians. It’s an easier way as well. “Relax, we won’t flood your facebook news feed!”
Post Question
Dear , Preparing for entrance exams? Register yourself for the free demo class from askiitians.
Resistance and Resistivity Table of Content...
Basic Concepts In electrostatics we have seen that...
Electrical Energy and Power Table of contents...
Mechanism of current flow in a metallic conductor...
Cells, EMF, Internal Resistance Table of Content...
Electric Current and Current Density Table of...
Meter Bridge Table of contents Wheatstone Bridge...
Specific Resistance of the Material of a wire...
Maximum Power Transfer Theorem Table of Content...
Combination of Resistors – Series and...
Int Introduction of Current Electricity Table of...
Variation of Resistivity with Temperature We have...
Measurement of an unknown resistance using a Post...
Drift of Electrons and the Origin of Resistivity...
Emf and Grouping of cells Table of Content...
Resistivity of Various Materials Table of contents...
Drift Velocity The average velocity attained by...
Temperature Dependence of Resistivity Table of...
Limitations of Ohm’s Law Table of contents...
Wheatstone Bridge Table of contents Introduction...
Solved Examples of Comlicated Circuits...
Effective Grouping of Cells The flow of current...
Kirchhoff’s Law Table of contents Current...
Potentiometer Table of contents Potentiometer and...
Thermal and Chemical Effect of current Table of...
Ohm’s Law Table of contents Voltage, Current...
Constant Potential Difference Table of Content...
Complicated Circuits As the name suggests,...
Errors The major systematic errors in this...
Cells in Series and in Parallel Table of Content...
