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

Asked in JEE Main 2005 · Terminal voltage and internal resistance

Answer: (1) zero

Step-by-step solution

Current into the load: I=E/(R+r).

If r R, then I≈E/r, which does not change when the load R changes: a constant-current source.

If r=0, the terminal voltage stays constant, but I=E/R changes with the load.

Printed key is option (a), but the physics of a constant-current source gives option (d).

Why the other options are wrong

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