In domestic electrical wiring,what is the red-colored insulated wire used for?

The direction of the magnetic field produced by a current-carrying straight wire depends on which of the following?

$(a)$ Describe an activity to determine the direction of magnetic field produced by a current-carrying straight conductor. Also,show that the direction of the magnetic field is reversed on reversing the direction of current.
$(b)$ An $\alpha$-particle (which is a positively charged particle) enters a uniform magnetic field at right angles to it as shown below. Stating the relevant principle,explain in which direction will this $\alpha$-particle move?

Write any one method to induce current in a coil.

What does the direction of the thumb indicate in the Right-Hand Thumb Rule? In what way is this rule different from Fleming's Left-Hand Rule?

Define a solenoid. How is it different from a coil?