If a ball falls from a girls hand, how does its speed change?

Yes

Explanation:

At initial condition the ball is in rest because girl hold the ball.But after when girl release the ball the due to gravity it speed goes to increase and become zero again when it touch the floor.

As we know that gravity  provides acceleration due to which velocity of ball increases.

Lets take the height of ball from the bottom was h ,so the velocity of ball just before when ball touch the bottom surface after falling from the hand of girl is V.

the higher the current the higher the mag field around it the higher the influence on the compass