Two Cells of Emfs 1.5 V and 2.0 V, Having Internal Resistances 0.2 Ω and 0.3 Ω, Respectively, Are Connected in Parallel. Calculate the Emf and Internal Resistance of the Equivalent Cell. - Physics

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Two cells of emfs 1.5 V and 2.0 V,  having internal resistances 0.2 Ω and 0.3 Ω, respectively, are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.

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Solution

Given:
E1=1.5 V

E2=2 V

r1=0.2 Ω

r2 =0.3 Ω

The effective emf of two cells connected in parallel can be calculated as follows: 

`E_(eff) = (E_1r_2+E_2r_1)/(r_1+r_2)`

`=> E_(eff) = (1.5xx0.3+2.0xx0.2)/0.5 = 1.7 V`

The effective resistance can be calculated as follows:

`R_(eff)= (r_1r_2)/(r_1+r_2)`

`=> R_(eff)= (0.2xx.03)/0.5`0.12 Ω

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2015-2016 (March) Delhi Set 1

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