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

Which scientist discovered that an electric current can be produced using a magnetic field?

An electron enters a magnetic field at right angles to it as shown in the figure. The direction of force acting on the electron will be:

With the help of which law or rule can the direction of a magnetic field be known?

$(a)$ State the function of a fuse in an electric circuit. How is it connected in the domestic circuit?
$(b)$ An electric fuse of rating $3 \, A$ is connected in a circuit in which an electric iron of power $1.5 \, kW$ is connected,which operates at $220 \, V$. What would happen? Explain.

$(a)$ An electric current is passed in a horizontal copper wire from east to west. Explain your observations when a compass needle is placed $(i)$ below this wire,$(ii)$ above the wire. Draw inference from your observations.
$(b)$ List the factors on which the strength of the magnetic field due to a straight conductor carrying current depend. How should these be changed to decrease magnetic field at a point?