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 lamps as shown, then
  • AThe value of $R$ for normal brightness of each lamp is $(3/4)$ $\Omega$
  • BThe value of $R$ for normal brightness of each lamp is $(21/4)$ $\Omega$
  • CTotal power dissipated in circuit when all lamps are normally bright is $24\,W$
  • DPower dissipated in $R$ is $21\,W$ when all lamps are normally bright
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