A student uses an electrical heater to investigate the change of state of liquid nitrogen. The liquid nitrogen is kept at its boiling point inside a vacuum-insulated flask placed on a digital balance.
The student measures the electrical energy supplied to the heater, EEE, and the corresponding mass of nitrogen vaporised, Δm\Delta mΔm. The student's results are shown in the graph below:
What is the specific latent heat of vaporisation of liquid nitrogen? Use the graph and the specific latent heat equation: ΔE=mL\Delta E = m LΔE=mL
2.0×10−1 J kg−12.0 \times 10^{-1}\text{ J\ kg}^{-1}2.0×10−1 J kg−1
2.0×102 J kg−12.0 \times 10^2\text{ J\ kg}^{-1}2.0×102 J kg−1
2.0×105 J kg−12.0 \times 10^5\text{ J\ kg}^{-1}2.0×105 J kg−1
5.0×105 J kg−15.0 \times 10^5\text{ J\ kg}^{-1}5.0×105 J kg−1