Four identical electrical lamps are labelled $1.5\,V$,$0.5\,A$,which describes the condition necessary for them to operate at normal brightness. $A$ $12\,V$ battery of negligible internal resistance is connected to the lamps as shown. Then:

  • A
    The value of $R$ for normal brightness of each lamp is $(3/4)\,\Omega$.
  • B
    The value of $R$ for normal brightness of each lamp is $(21/4)\,\Omega$.
  • C
    Total power dissipated in the circuit when all lamps are normally bright is $24\,W$.
  • D
    Power dissipated in $R$ is $21\,W$ when all lamps are normally bright.

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