The heat of atomisation of methane and ethane are $x \ kJ \ mol^{-1}$ and $y \ kJ \ mol^{-1}$ respectively. The longest wavelength $(\lambda)$ of light capable of breaking the $C-C$ bond can be expressed in $SI$ unit as :

  • A
    $\frac{hc}{1000}(\frac{y-6x}{4})^{-1}$
  • B
    $\frac{N_{A}hc}{250(4y-6x)}$
  • C
    $\frac{N_{A}hc}{250(y-6x)}$
  • D
    $N_{A}hc(y-\frac{6x}{4})^{-1}$

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