A bar magnet is held in place while another bar magnet is placed near it. The second bar magnet spins around and attaches to the first magnet on one end. Which statement is correct about the energy stored in the magnetic field?
Responses
The decrease in the energy stored in the system is proportional to the increase in kinetic energy.
The decrease in the energy stored in the system is proportional to the increase in kinetic energy. - not selected, this is the correct answer
The increase in the energy stored in the system is proportional to the increase in kinetic energy.
The increase in the energy stored in the system is proportional to the increase in kinetic energy. - incorrect
The increase in the energy stored in the system is proportional to the decrease in kinetic energy.
The increase in the energy stored in the system is proportional to the decrease in kinetic energy. - no response given
The decrease in the energy stored in the system is proportional to the decrease in kinetic energy.
The decrease in the energy stored in the system is proportional to the decrease in kinetic energy. - no response given
This is incorrect because the energy stored in the field decreases.
explain why this answer is correct
When the second bar magnet spins around and attaches to the first bar magnet, the energy stored in the magnetic field decreases as the magnets align and release energy. This energy is converted into kinetic energy as the second magnet spins and moves towards the first magnet. Therefore, the decrease in the energy stored in the system is proportional to the increase in kinetic energy.
Which of the following factors would decrease the magnetic field strength of an electromagnet?
Responses
increasing the current or using a higher-voltage power source
increasing the current or using a higher-voltage power source - no response given
increasing the number of turns in the coil of wire
increasing the number of turns in the coil of wire - no response given
increasing the distances between the turns of the coil
increasing the distances between the turns of the coil - not selected, this is the correct answer
using an iron core or nail
using an iron core or nail - incorrect
Using an iron core or nail will increase the magnetic field strength of an electromagnet.
explain why this answer is correct
By increasing the distances between the turns of the coil, the magnetic field strength of an electromagnet would decrease. This is because having more space between the turns of the coil reduces the efficiency of the magnetic field generated by the current flowing through the wire. Increasing the distances between the turns of the coil weakens the magnetic field produced by the electromagnet.
Which pair of objects will have an attractive electric force?
Pair
Object 1 Charge
Object 2 Charge
A
-2
-1
B
-3
+1
C
+3
+1
D
+1
+2
Responses
Pair B
Pair B - not selected, this is the correct answer
Pair C
Pair C - incorrect
Pair D
Pair D - no response given
Pair A
Pair A - no response given
The objects in Pair C will have a repulsive electric force.
explain why this is the correct answer
The correct answer is Pair B because objects with opposite charges will experience an attractive electric force. In Pair B, Object 1 has a charge of -3 and Object 2 has a charge of +1, which are opposite charges. So, they will attract each other due to the opposite charges.
In Pair C, both Object 1 and Object 2 have positive charges, which will result in a repulsive electric force between them, not an attractive force. Therefore, Pair C will have a repulsive electric force, not an attractive force.