Question

Which electric bulb is required for the observation?

Options

• A clear glass electric bulb with a straight, thin filament

• A clear glass electric bulb with a red colour filter

• A clear glass electric bulb with a narrow, uniform slit

• A clear glass electric bulb with a blue colour filter

Answer 1

The bulb must have a clear glass enclosure and a straight, thin filament. The filament is viewed through the slit.