@rajananthini,
I doubt that any American company would give you a job just based on a written test. You would have to have an in-person interview or at least a phone screen.
If you're that afraid, take classes in acting and work to overcome your shyness. You won't be able to phone in your job, either. Even if you work from home 100% of the time, you will still need to occasionally call in, either on the phone or on Skype.