The closer together magnetic field lines are, the _____ the magnetic force.
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.
1. stronger
2. true
3. electromagnet
4. The Doppler Effect
I promise this is 100%
https://quizlet.com/7305529/magnets-flash-cards/
http://www.ece.neu.edu/fac-ece/nian/mom/electromagnets.html
The closer together magnetic field lines are, the _____ the magnetic force.
A. closer
B. farther
C. stronger
D. weaker
The closer together magnetic field lines are, the stronger the magnetic force.
To understand this concept, you can consider the magnetic field lines as a representation of the strength and direction of the magnetic field around a magnet or a current-carrying wire. The density of the magnetic field lines indicates the strength of the magnetic field at a particular point. When the field lines are closer together, it means that the magnetic field is stronger in that region. Therefore, the magnetic force is stronger when the magnetic field lines are closer together.
Magnetic poles always exist in north-south poles.
This statement is true. Magnets have two poles, commonly referred to as the north pole and the south pole. These poles always come in pairs, and no single pole can exist on its own. Like poles repel each other, while opposite poles attract each other. So, if you were to cut a magnet in half, you would not end up with a single north or south pole; instead, you would have two smaller magnets, each with its own north and south pole.
An electromagnet is an electric circuit that produces a magnetic field.
This is the correct answer. An electromagnet is a type of magnet that is created by passing an electric current through a coil of wire. The electric current generates a magnetic field around the coil, which can be controlled by adjusting the strength of the current. Electromagnets are used in various devices where a temporary or controllable magnetic field is needed, such as motors, generators, and magnetic levitation systems.
A car's horn sounds different as the car approaches. The change in pitch is due to the Doppler effect.
You are correct. The change in pitch of a car's horn as it approaches is due to the Doppler effect. The Doppler effect is a phenomenon observed with waves (including sound waves) when there is relative motion between the source of the waves and an observer. In the case of a moving car, as the car approaches, the sound waves emitted by the horn get compressed, resulting in a higher frequency and higher pitch. Once the car passes and moves away from the observer, the sound waves get stretched, resulting in a lower frequency and lower pitch.