Amajor difference between ac and dc electricity is that a) the current in ac electricity varies in magnitude and direction. b) the current in dc electricity varies in magnitude and direction. c) the voltage in ac electricity varies in magnitude and direction. d) the voltage in dc electricity varies in magnitude and direction.

A)the current in AC electricity varies in magnitude and direction.

C)the voltage in AC electricity varies in magnitude and direction.

Explanation:

In DC current and voltage the direction of current will not change with time and it always remains the same.

So here in DC voltage and DC current the magnitude may change with time but the direction will always remain same

While in AC voltage and AC current the direction of AC will change with time

periodically.

So here magnitude and direction both will change in AC current and AC voltage.

so the correct answer is

A)     the current in AC electricity varies in magnitude and direction.

C)the voltage in AC electricity varies in magnitude and direction.

b

explanation:

bc its just b

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.