Manipal MET2015PhysicsCurrent Electricity
Under what conditions current passing through the resistance R can be increased by short circuiting the battery of emf E₂ ? The internal resistances of the two batteries are r₁ and r₂ respectively.
Options
- AE₂ r₁ E₁ (R+r₂ )
- BE₁ r₂ E₂ (r₁+R )
- CE₂ r₂ E (R+r₂ )
- DE₁ r₁ E₂ (r₁+R )
Correct answer
B. E₁ r₂ E₂ (r₁+R )
Step-by-step solution
The current through the circuit before the battery of emf E₂ is short circuited, is i₁= E₁+E₂ r₁+r₂+R ...(i) After short circuiting the battery of emf E₂ , current through the resistance R would be i₂= E₁ R+I₁ ...(ii) Since, from Eqs. (i) and (ii), we get i₂ i₁ E₁ R+r₁ E₁+E₂ R+r₁+r₂ This gives E₁ r₂ E₂ (R+r₁ )