If several negative charges surround a large positive charge, the total force on a far away charge is reduced. What is this effect called

this effect is called SCREENING

Explanation:

When a positive charge is surrounded by several negative charges at a long distance, an apparent decrease in the positive charge is observed, this effect is called SCREENING and is noticeable in multielectronic atoms

This effect is responsible for the decrease in ionization energy in the larger atoms.

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer