Draw the pattern of magnetic field lines due to a current-carrying solenoid.

Identify the poles of the magnet in the given figures ($1$) and ($2$).

Figure $\left(1\right)$

  
 Figure $\left(2\right)$                                                                                                                                                                                        

An electron enters a uniform magnetic field at right angles to it as shown in the figure below. In which direction will this electron move? State the rule applied by you in finding the direction of motion of the electron.

A student, while studying the force experienced by a current-carrying conductor in a magnetic field records the following observations:
(i) The force experienced by the conductor increases as the current is increased.
(ii) The force experienced by the conductor decreases as the strength of the magnetic field is increased.
Which of the two observations is correct and why?

How does the strength of the magnetic field at the centre of a circular coil of a wire depend on
(a) radius of the coil?
(b) number of turns of wire in the coil?