Static on a color television appears as black and white rather than multicolored due to the way color information is encoded and transmitted in television signals.
In a color television system, color information is conveyed through a process called chrominance modulation, while brightness information is conveyed through luminance modulation. The color information is combined with the brightness information to create a composite video signal.
When static is displayed on a television screen, it usually occurs when there is no or weak reception of a broadcast signal. In such cases, the color information is often lost or distorted, while the brightness information may still be partially received. As a result, only the luminance component is typically displayed, resulting in a black and white image.
The chrominance information, which is responsible for color reproduction, consists of two color difference signals: the red-minus-luminance (R-Y) and blue-minus-luminance (B-Y) signals. These signals are combined with the luminance signal (Y) to recreate the full-color image on the screen. However, in the absence of a proper color signal, the television is unable to reconstruct the color information and displays only the luminance component, resulting in a grayscale or black and white appearance.
Therefore, when you see static on a color television, it is because the color information is not being properly received or transmitted, leading to the loss of color and the display of a monochrome image.