A potential difference across the terminals of a battery is $50 \mathrm{~V}$ when 11 A current is drawn and $60 \mathrm{~V}$,when 1 Acurrent is drawn. The emf and the internal resistance of the battery are

• A

  $62 \mathrm{~V}, 2 \Omega$
• B

  $63 \mathrm{~V}, 1 \Omega$
• Correct answer
  C

  $61 \mathrm{~V}, 1 \Omega$
• D

  $64 \mathrm{~V}, 2 \Omega$

Solution

For a closed circuit cell supplies a constant current in the circuit.
For cell $\mathrm{E}=\mathrm{V}+\mathrm{Ir}$ For $\mathrm{V}=50 \mathrm{~V}$ $E=50+11 r$ Similarly, for $\mathrm{V}=60 \mathrm{~V}$ $E=60+r$ From eqs. (i) and (ii), we get $E=61 \mathrm{~V}$

Hence, the correct answer is option: 'C'.