Maximum density of $H_2O$ is at temperature

In a mercury thermometer, the ice point (lower fixed point) is marked as $10^{\circ}$ and the steam point (upper fixed point) is marked as $130^{\circ}$. At $40^{\circ} C$ temperature, what will this thermometer read (in $^{\circ}$)?

Two thermometers $X$ and $Y$ have ice points marked at $15^{\circ}$ and $25^{\circ}$ and steam points marked as $75^{\circ}$ and $125^{\circ}$ respectively. When thermometer $X$ measures the temperature of a bath as $60^{\circ}$ on it,what would thermometer $Y$ read (in $^{\circ}C$) when it is used to measure the temperature of the same bath?

$A$ calorie is defined as the amount of heat required to raise the temperature of $1 \, g$ of water by $1^{\circ} C$. Under which of the following conditions is this defined?

The triple point of water is

Recently,the phenomenon of superconductivity has been observed at $95\, K$. This temperature is nearly equal to ......... $^oF$.