JEE Main · 2005 · 08 May 2005 · Offline · Current Electricity

An energy source will supply a constant current into the load of its internal resistance is

Answer: (B)

Solution

A constant-current source must deliver a current

I = \frac{E}{R + r}

that scarcely changes as the load

R

varies. That demands the internal resistance

r

to dominate,

r ≫ R

, so that

I \approx \frac{E}{r}

stays fixed whatever the load; the internal resistance must be very large compared with the load resistance.

JEE Main · 2005 · 08 May 2005 · Offline · Single correct option