A well insulated substance in solid state is heated at a constant rate until it vaporizes completely. The temperature-time graph of the substance is shown below . Which of the following statements is//are true?

State whether the following statement is true or false : The ignition temperature of all combustible substance is same.

A solid substance is at 30^(@)C . To this substance heat energy is supplied at a constant rate. Then temperature versus time graph is as shown in the figure. The substance is in liquid state for the portion (of the graph)

State true or false. When heat is supplied to a substance, it always raises the temperature of substance.