To determine the melting point of ice, a thermometer is suspended in a beaker half filled with ice and kept at the room temperature. Which thermometer reading should be noted as the melting point of ice?
1
The temperature when all the ice taken melts and water remains.
2
The temperature when the ice just starts to melt.
3
When the mercury level in the thermometer remains constant at a particular temperature.
4
When the temperature just begins to increase from -2°C.