If the velocity of the charged particle is parallel to the magnetic field (or antiparallel), then there is no force because sin(θ) equals zero. When this occurs, the charged particle can maintain its straight line motion, even in the presence of a strong magnetic field. Imagine holding the conductor with your right hand and the thumb pointing in the direction of the flow of current, the fingers point in the direction of the magnetic field.

The rule can be used to find the direction of the magnetic field, rotation, spirals, electromagnetic fields, mirror images, and enantiomers in mathematics and chemistry. To understand how Lenz’s Law will affect this system, we need to first determine whether the initial magnetic field is
increasing or decreasing in strength. As the magnetic north pole gets closer to the loop, it causes the existing magnetic
field to increase. Since the magnetic field is increasing, the induced current and resulting induced magnetic field will
oppose the original magnetic field by reducing it. This means that the primary and secondary magnetic fields will occur in
opposite directions. When the existing magnetic field is decreasing, the induced current and resulting induced magnetic
field will oppose the original, decreasing magnetic field by reinforcing it.

Electrical Technology

If the magnetic field in the loop is decreasing, then the induced magnetic field vector will
occur in the same direction to replace the original field’s decrease. Next, align your thumb in the direction of the
induced magnetic field and curl your fingers. If we consider current flow as the movement of positive charge carriers (conventional current) in the above
image, we notice that the conventional current is moving up the page. Since a conventional current is composed
of positive charges, then the same current-carrying wire can also be described as having a current with negative
charge carriers moving down the page.

Helices are either right- or left-handed, with curled fingers giving the direction of rotation and thumb giving the direction of advance along the z-axis. For right-handed coordinates, the right thumb points along the z-axis in the positive direction and the curling motion of the fingers of the right hand represents a motion from the first or x-axis to the second or y-axis. So placing a steel nail in the centre of a solenoid boosts its magnetic field strength by a factor of 100 — which would make the solenoid roughly as strong as a typical bar magnet.

Positive and Negative Torques

Torques that
face out from the paper should be analyzed as positive torques, while torques that face inwards should be analyzed
as negative torques. Thirdly, establish the direction of the field lines using the standard right hand grip rule (3). To go in reverse order for no particular reason, I don’t like using the second method because it involves a tricky mental rotation of the plane of view by 90 degrees to imagine the current direction as viewed when looking directly at the ends of the magnet. In the diagram above, the thumb aligns with the z axis, the index finger aligns with the x axis and the middle finger aligns with the y axis. A solenoid is an electromagnet made of a wire in the form of a spiral whose length is larger than its diameter.

The relative permeability of a material is a measurement of how ‘transparent’ it is to magnetic field lines. The relative permeability of pure iron is about 1500 (no units since it’s relative permeability and we are comparing its magnetic properties with that of empty space). However, the core material used in the school laboratory is more likely to be steel rather than iron, which has a much more modest relative permeability of 100. The N and S-poles of a solenoid can change depending on the direction of current flow and the geometry of the loops.

Ampère’s right-hand grip rule

When an electric current passes through a solenoid, it creates a magnetic field. To use the right hand grip rule in
a solenoid problem, point your fingers in the direction of the conventional current and wrap your fingers as if they
were around the solenoid. Your thumb will point in the direction of the magnetic field lines inside the solenoid. Note
that the magnetic field lines are in the opposite direction outside the solenoid. The right hand grip rule (also known as right hand screw rule) tells you the direction of a magnetic field due to a current.

Thus, the induced magnetic field will have the
same direction as the original magnetic field. In the first wire, the flow of positive charges up the page
indicates that negative charges are flowing down the page. Using the right hand rule tells us that the magnetic
force will point in the right direction. In the second wire, the negative charges are flowing up the page, which
means the positive charges are flowing down the page. As a result, the right hand rule indicates that the magnetic
force is pointing in the left direction. When the magnetic flux through a closed loop conductor changes, it induces a current within the loop.

Over many centuries, by patient trial-and-error, humans learned how to magnetise a piece of iron to make a permanent magnet. (The origin of the name is probably not what you think — it’s named after the region, Magnesia, where it was first found). In ancient times, lodestones were so rare and precious that they were worth more than their weight in gold. One of the best ways to help students become confident using the right hand rule, is to perform a visual demonstration that helps them recognize and correct their misconceptions about orthogonal relationships and coordinate systems.

Right Hand Rule for a Cross Product

In vector calculus, it is necessary to relate the normal vector to a surface to the curve bounding it. For a positively-oriented curve C, bounding a surface S, the normal to the surface n̂ is defined such that the right thumb points in the direction of n̂, and the fingers curl along the orientation of the bounding curve C. When an observer looks at the facing end of the solenoid, if current flows in the clockwise direction, the the facing end of the solenoid coil behaves like the South Pole “S” and the second end behaves like the North Pole “N”. If you hold the coil or a solenoid in the right hand so that the four fingers curl around the coil or solenoid, then the curly figures show the direction of the current and the thumb represents the North Pole of the coil. All of these rules, in the end, come from the right hand cross product rule anyways. There are lots of things you can do with your right hand, though, so I wouldn’t be surprised if one of them gave you the right direction.

For left-handed coordinates, the left thumb points along the z-axis in the positive direction and the curling motion of the fingers of the left hand represents a motion from the first or x-axis to the second or y-axis. Lenz’s law of electromagnetic induction is another topic that often seems counterintuitive, because it requires
understanding how magnetism and electric fields interact in various situations. To apply the right hand rule to cross products, align your fingers and thumb at right angles. Then, point your index
finger in the direction of vector a and your middle finger in the direction of vector b. Your right thumb will point
in the direction of the vector product, a x b (vector c). The plane formed by the direction of the magnetic field and the charged particle’s velocity is at a right angle to the force.

The field lines seem to begin at the north pole and end at the south pole. A conventional current is composed of moving charges that are positive in nature. When a conventional current moves through a conducting wire,
the wire is affected by a magnetic field that pushes it. We can use the right hand rule to identify the direction of the force acting on the
current-carrying wire. In this model, your fingers point in the right hand gripping rule direction of the magnetic field, your thumb points in the direction of the
conventional current running through the wire, and your palm indicates the direction that the wire is being pushed (force). The first method I dislike because it creates confusion with the ‘proper’ right hand grip rule which tells us the direction of the magnetic field lines around a long straight conductor and which I’ve written about before .

The region inside the solenoid has a very strong and nearly uniform magnetic field. By ‘uniform’ we mean that the field lines are nearly straight and equally spaced meaning that the magnetic field has the same strength at any point. Imagine the wire to be grasped in the right hand with the thumb pointing along the wire in the direction of the current. The direction of the fingers will give the direction of the magnetic flux (Fig. 36.4). A helix is a curved line formed by a point rotating around a center while the center moves up or down the z-axis.

If you point your thumb in the direction of the current, your fingers will curl in the direction of the magnetic field. The right hand rule is used to determine the direction of the magnetic field lines and current around a straight current carrying conductor, solenoid or coil inductor. While a magnetic field can be induced by a current, a current can also be induced by a magnetic field.

We can use
the second right hand rule, sometimes called the right hand grip rule, to determine the direction of the magnetic
field created by a current. To use the right hand grip rule, point your right thumb in the direction of the current’s
flow and curl your fingers. The direction of your fingers will mirror the curled direction of the induced magnetic field.

• The region inside the solenoid has a very strong and nearly uniform magnetic field.
• To apply the right hand rule to Lenz’s Law, first determine whether the magnetic field through the loop is increasing or
  decreasing.
• To use the right hand rule in torque problems, take your right hand and point it in the
  direction of the position vector (r or d), then turn your fingers in the direction of the force and your thumb will point
  toward the direction of the torque.
• The field lines seem to begin at the north pole and end at the south pole.

To apply the right hand rule to Lenz’s Law, first determine whether the magnetic field through the loop is increasing or
decreasing. Recall that magnets produce magnetic field lines that move out from the magnetic north pole and in toward the
magnetic south pole. If the magnetic field is increasing, then the direction of the induced magnetic field vector will be
in the opposite direction.