Final answer:
When electricity is passed through a gas, it produces a line spectrum of light, whereas a hot object gives off a continuous spectrum of light. This difference is due to the properties of excited atoms and the nature of the emitted light.
Step-by-step explanation:
When electricity is passed through a gas and light is emitted, the light produced forms a line spectrum. This is because each emission line consists of a single wavelength of light. The line spectrum is caused by the excited atoms de-exciting and emitting specific wavelengths of light. In contrast, when a hot object gives off light, it produces a continuous spectrum because it emits light across a range of wavelengths. The difference between the line spectrum and continuous spectrum is due to the properties of excited atoms and the nature of the light emitted.