Ten identical cells, each of emf E and internal resistance r , are connected in series and the combination is short-circuited by a thick wire of zero resistance. The steady current in the circuit is I_s . The same ten cells are then connected in parallel and the combination is similarly short-circuited, producing a steady current I_p . The ratio I_p I_s is:

Step-by-step solution

When 10 identical cells of emf E and internal resistance r are connected in series, the equivalent emf is 10E and the equivalent internal resistance is 10r . The short-circuit current I_s is given by: I_s = 10E 10r = E r When the same 10 cells are connected in parallel, the equivalent emf remains E and the equivalent internal resistance becomes r 10 . The short-circuit current I_p is given by: I_p = E r 10 = 10E r The required ratio is: I_p I_s = 10E r E r = 10 Answer: 10