Question

N lamps each of resistance r, are fed by a machine of resistance R. If light emitted by any lamp is proportional to the square of the heat produced, prove that the most efficient way of arranging them is to place them in parallel arcs, each containing n lamps, where n is the integer nearest to

• A. \((\frac {r}{NR})^{\frac 32}\)
• B. \((\frac {NR}{r})^{\frac 12}\)
• C. \((NRr)^{\frac 32}\)
• D. \((NRr)^{\frac 12}\)

Answer 1

The Correct Option is B

The correct option is (B): \((\frac {NR}{r})^{\frac 12}\).