Check whether the following statements are True or False:
$(a)$ The equation to convert Celsius temperature to Fahrenheit is $t^{\circ}F = \frac{5}{9}t^{\circ}C + 32$.
$(b)$ For an ideal gas,absolute zero temperature is $273.15^{\circ}C$.
$(c)$ The volume of water is maximum at $4^{\circ}C$.
$(d)$ The temperature gradient is negative if a cube block is heated at the cold end and heat transfers to the hot end.

(NONE) False. The correct conversion formula is $t^{\circ}F = \frac{9}{5}t^{\circ}C + 32$.
$(b)$ False. Absolute zero temperature is $-273.15^{\circ}C$.
$(c)$ False. The density of water is maximum at $4^{\circ}C$,which means its volume is minimum at this temperature.
$(d)$ False. Heat flows from a higher temperature to a lower temperature. If heat is transferred from the cold end to the hot end,the temperature gradient would be positive in the direction of heat flow.