In case of fluid flowing on horizontal surface the flow of fluid becomes unsteady when Reynolds number (Rn) is

If the shape of the liquid surface is curved, then

A black body radiates maximum energy at wavelength '$\lambda$' at temperature $T_1$ and its emissive power is E. When the temperature of the body is changed to $T_2$, it radiates maximum energy at wavelength $\dfrac{2\lambda}{3}$, then the emissive power will become

A body cools from a temperature $3\theta$ to $2\theta$ in 10 minute. The room temperature is $\theta$. The temperature of the body at the end of the next 10 minute is '$x$'. Assuming that Newton's law of cooling is applicable, the value of '$x$' will be