Final answer:
The filament used in shadow casting usually contains b. titanium together with carbon.
Step-by-step explanation:
The filament used in shadow casting usually contains b. titanium together with carbon. This combination is often used because titanium has a high melting point and does not burn easily, while carbon provides the necessary electrical conductivity.
The titanium-carbon filament is commonly found in stage lighting instruments, such as spotlights and follow spots, where it produces a bright and focused beam of light.