question_answer

The potential difference across the terminals of a battery is 50V when 11 A current is drawn and 60V when 1 A current is drawn. The emf and the internal resistance of the battery, are

A)  \[\frac{\omega M}{M+m}\]                      

B)  \[{{a}_{c}}={{k}^{2}}{{r}^{2}}{{t}^{2}},\]

C)  \[2mk{{r}^{2}}t\]            

D)  \[mk{{r}^{2}}{{t}^{2}}\]

Correct Answer: C

Solution :

                For a closed circuit, cell supplies a constant current in the circuit.       Equation of cell \[{{a}_{c}}={{k}^{2}}{{r}^{2}}{{t}^{2}},\]                 \[2mk{{r}^{2}}t\] \[mk{{r}^{2}}{{t}^{2}}\]                 ....(i) Similary, for \[m{{k}^{2}}{{r}^{2}}t\]  \[m{{k}^{2}}r{{t}^{2}}\]                ......(ii) From Eqs. (i) and (ii), we have                 \[1\text{ }km/h\] Substituting the value of r in Eq (i), we get                 \[\text{3 }km/h\]