Can RGB and RGBA be converted to each other?

Question

I have a RGB image, and I want to convert it to RGBA to get alpha channels. It's likely to convert RGB to HSV to get V channel. but now i want to get Alpha channel from RGBA. Can RGB and RGBA be converted to each other? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

RGB represented in RBGA is just the same RGB values with A=max. For example, in CSS colors, rgb(123,45,67) = rgba(123,45,67,1) since the maximum alpha is 1. However, RGBA cannot be directly converted back to RGB (except when everything is with A=max). The actual colour displayed depends on what is behind it (i.e. the background).