B. Wang et al., CAN A NONEXTREMAL REISSNER-NORDSTROM BLACK-HOLE BECOME EXTREMAL BY ASSIMILATING AN INFALLING CHARGED-PARTICLE AND SHELL, Physical review. D. Particles and fields, 57(8), 1998, pp. 5284-5286
By using the gedanken experiments suggested by Bekenstein and Rosenzwe
ig, we show that a nonextremal Reissner-Nordstrom black hole cannot tu
rn into an extremal one by assimilating an infalling charged particle
and a charged spherical shell.