(a) The given figure shows the current passing through the straight conductor XY.

(i) Copy the diagram and draw the magnetic field lines when current flows from conductor X to Y.

(ii) Name and state the rule used in determining the direction of the magnetic field lines in the situation given above.

(iii) State Fleming's left hand rule. Using this rule, determine the direction of force applied on an electron entering a uniform magnetic field as shown in the figure.

OR

(b) (i) Define the term solenoid. Draw the pattern of the magnetic field lines in and around a current carrying straight solenoid. Mark on the pattern the (i) direction of current, (ii) direction of field lines near the ends of the solenoid, and (iii) region where the magnetic field is uniform.

(ii) How would you make an electromagnet using a current carrying solenoid?

(a) (i) The magnetic field lines are shown in the figure below. The direction of the magnetic field lines can be determined using the right-hand thumb rule. When the thumb points in the direction of the current, the fingers will wrap around the conductor in the direction of the magnetic field lines. (ii) The rule used to determine the direction of the magnetic field lines is the right-hand thumb rule. (iii) Fleming's left-hand rule states that if the thumb, index finger, and middle finger of the left hand are held perpendicular to each other, with the thumb pointing in the direction of the magnetic field, the index finger pointing in the direction of the current, and the middle finger pointing in the direction of the force on the conductor, then the force on the conductor will be in the direction of the middle finger. Using this rule, we can determine that the force on the electron entering the uniform magnetic field will be in the direction of the middle finger, which is perpendicular to both the magnetic field and the current. (b) (i) A solenoid is a coil of wire that carries an electric current. The pattern of the magnetic field lines in and around a current-carrying straight solenoid is shown in the figure below. The direction of the current is shown by the arrows on the solenoid. The direction of the magnetic field lines near the ends of the solenoid is shown by the arrows on the magnetic field lines. The region where the magnetic field is uniform is shown by the shaded area inside the solenoid. (ii) An electromagnet can be made using a current-carrying solenoid by wrapping a coil of wire around a core of ferromagnetic material, such as iron. When an electric current flows through the coil, a magnetic field is generated, which magnetizes the core and creates an electromagnet.