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Upper bound on the electric charge of a black hole


THROUGH an analysis of reversible transformations of black holes, Christodoulou and Ruffini1 have shown that the energy of a rotating, charged black hole is given by where mir is the irreducible mass of the black hole, Q its charge and L its angular momentum. They have also shown1 that for a given irreducible mass, the charge and angular momentum must satisfy the condition Once the equality is satisfied, no more charge or angular momentum can be added to the black hole without increasing mir.

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  1. 1

    Christodoulou, D., and Ruffini, R., Phys. Rev., D 4, 3552 (1971).

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  2. 2

    Penrose, R., Rivista Nuovo Cim., numero speciale 252 (1969).

  3. 3

    Schwinger, J., Phys. Rev., 82, 664 (1951).

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ZAUMEN, W. Upper bound on the electric charge of a black hole. Nature 247, 530–531 (1974).

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