A solid sphere of radius $1$ $cm$ and initial temperature of $25^{\circ}\:C$ is exposed to a gas stream at $100^{\circ}\:C$. For the solid sphere, the density is $10^{4}$ $kg/m^{3}$ and the specific heat capacity is $500\;J/(kg\:K)$. The density of the gas is $0.6$ $kg/m^{3}$ and its specific heat capacity is $10^{3}$ $J/(kg \:K)$. The solid sphere is approximated as a lumped system (Biot number « $1$) and all specific heats are constant. If the heat transfer coefficient between the solid and gas is $50$ $W/(m^{2} \: K)$, the time (in seconds) needed for the sphere to reach $95^{\circ}\:C$ is ______________ (rounded off to the nearest integer)
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