Choose all of the statements that are true about electromagnets: 1. electromagnets are permanent and always have a magnetic field around them. 2. electromagnets can be made stronger by adding more coils to the solenoid. 3. electromagnets can be made stronger by increasing the strength of the electrical source. 4. none of the above.

2. electromagnets can be made stronger by adding more coils to the solenoid.

3. electromagnets can be made stronger by increasing the strength of the electrical source.

Explanation:

Electromagnets are not permanent, they act as magnets when current runs through its coils. They can be stronger by increase the current that goes through the coil surrounding them,. This can be done two ways: 1) increasing the actual current intensity, or 2) increasing the number of coils that wrap around them.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force