The decay constant of radioactive sample is L The haif life and mean life of the sample are respectively given by

• A

  $1/\mathrm{\lambda }\text{ and }{\log }_{\mathrm{e}}2/\mathrm{\lambda }$

• B

  ${\log }_{\mathrm{e}}2/\mathrm{\lambda }\text{ and }1/\mathrm{\lambda }$

• C

  ${\mathrm{\lambda log}}_{\mathrm{e}}2\text{ and }1/\mathrm{\lambda }$

• D

  $1/\mathrm{\lambda }\text{ and }{\mathrm{\lambda log}}_{\mathrm{e}}2$