Key Concepts. 1  The electrons on the outermost energy level of the atom are called valence electrons. 2  The valence electrons are involved in bonding one atom to another. 3  The attraction of each atomâs nucleus for the valence electrons of the other atom pulls the atoms together.
NTSC is the format used in the United States and Canada. NTSC stands for National Television Standard Committee which established the American TV broadcast TV standard as a 525 line broadcast. The NTSC system has higher frame rate (60 Hz) which reduces visible flicker and picture noise.
The two most common video standards used are NTSC and PAL.NTSC is the video system or standard used in North America and most of South America. In NTSC, 30 frames are transmitted each second. Each frame is made up of 525 individual scan lines.PAL is the predominant video system or standard mostly used overseas.