The closer together magnetic field lines are, the _____ the magnetic force.

Question

closer
farther
stronger
weaker

Magnetic poles always exist in north-south poles.

true***
false

A(n) _____ is an electric circuit that produces a magnetic field.

magnetic battery
electromagnet
coil magnet
coil circuit

A car's horn sounds different as the car approaches. The change in pitch is due to ________. (1 point)
electromagnetism
the Doppler effect***
the absorption of sound
the creation of a vacuum

100% sure about the second one and last one. I dunno about the rest.

Answer 1

https://quizlet.com/7305529/magnets-flash-cards/

http://www.ece.neu.edu/fac-ece/nian/mom/electromagnets.html

Answer 2

1. stronger
2. true
3. electromagnet
4. The Doppler Effect

I promise this is 100%

Answer 3

The closer together magnetic field lines are, the _____ the magnetic force.
A. closer
B. farther
C. stronger
D. weaker