PLEASE HELP ME WITH THIS ONE QUESTION Which of the following is true about an electromagnet? (Select all that apply.)

A) Decreasing the number of coils around the core makes a strong magnet.

B) Decreasing the current flowing through the wire makes a stronger magnet.

C) Increasing the current flowing through the wire makes a strong magnet.

D) Adding more coils around the core makes a stronger magnet.

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

The star betelgeuse is about 600 light-years away. if it explodes tonight, a. we'll know because debris from the explosion will rain down on us from space.b. we'll know it immediately because it will be brighter than the full moon in the sky.c. we won't know about it until 600 years from now.d. none of the above.

Although longitudinal waves can travel through all media types what is the disadvantage of this type of wave transmission? a) he efficiency of he wave transmission is greatly diminished as the media becomes less dense b) the oscillation of one set of particles has a huge impact on neighboring particles c) particles become too close together as they bump into each other making it more likely to hit other particles down the line