In mathematics and physics, the right-hand rule is a common mnemonic for understanding the orientation of axes in three-dimensional space. It is also a convenient method for quickly finding the direction of the cross product of two vectors. Rather than a mathematical fact, it is a convention, closely related to the convention that rotation around a vertical axis is positive if it is counterclockwise and negative if it is clockwise. Since the threads of a screw are in circular shape, the same is the case for magnetic field lines (which are in circular form). Torque problems are often the most challenging topic for first year physics students. 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. This also tells us that magnetic monopoles (that is to say, isolated N and S poles) are impossible. Ampère’s right-hand grip rule 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. Rules Guy: Is it legal to putt one-handed? – Golf.com Rules Guy: Is it legal to putt one-handed?. Posted: Fri, 31 Mar 2023 07:00:00 GMT [source] Yes, the Lorentz force law holds, so whatever rule you’re doing with your right hand must be wrong. The direction of the current in the last diagram is shown using the ‘dot and cross’ convention which, by a strange coincidence, I have also written about before . This is a consequence of Maxwell’s second equation of Electromagnetism (one of a system of four equations developed by James Clark Maxwell in 1873 that summarise our current understanding of electromagnetism). Corkscrew Rule The induced current creates a secondary magnetic field that opposes the original change in flux that initiated the induced current. The strength of the magnetic field passing through a wire coil determines the magnetic flux. Magnetic flux depends on the strength of the field, the area of the coil, and the relative orientation between the field and the coil, as shown in the following equation. When an electric current passes through a straight wire, it induces a magnetic field. To apply the right hand grip rule, align your thumb with the direction of the conventional current (positive to negative) and your fingers will indicate the direction of the magnetic lines of flux. 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. The direction of flux lines of magnetic field, motion of the conductor and induced EMF and current can be found by Fleming’s left hand and right hand rules which we have discussed in the previous post. The N and S-poles of a solenoid can change depending on the direction of current flow and the geometry of the loops. The plane formed by the direction of the magnetic field and the charged particle’s velocity is at a right angle to the force. Since the field lines are heading into this end of the solenoid, we can conclude that the right hand side of this solenoid is, in fact, a south-seeking pole. Since the field lines are emerging from X, we can confidently assert that this is a north-seeking pole, while Y is a south-seeking pole. Similarly, When the observer sees at the facing end of the coil, if current flows in the anticlockwise direction, then the facing end of the coil behaves like a North Pole “N” and the second end behaves like the South Pole “S”. It is based on corkscrew which is a tool used to open/remove the cork from a bottles). Torques that occur in a counter clockwise direction are positive torques. Alternatively, torques that occur in the clockwise direction are negative torques. Helices and screws 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. Recall that magnets produce magnetic field lines that move out from the magnetic north pole and in toward the magnetic south pole. Note that the magnetic field lines are in the opposite direction outside the solenoid. All of these rules, in the end, come from the right hand cross product rule anyways. To use the right hand grip rule, point your right thumb in the direction of the current’s flow and curl your fingers. Magnetic flux depends on the strength of the field, the area of the coil, and the relative orientation between the field and the coil, as shown in the following equation. Because the force occurs at a right angle to the plane formed by the particle’s velocity and the magnetic field, we can use the right hand rule to determine their orientation. The right hand rule is a hand mnemonic used in physics to identify the direction of axes or parameters that point in three dimensions. Invented in the 19th century by British physicist John Ambrose Fleming for applications in electromagnetism, the right hand rule is most often used to determine the direction of a third parameter right hand gripping rule when the other two are known (magnetic field, current, magnetic force). There are a few variations of the right hand rule, which are explained in this section. A Danish physicist Hans Christian Orsted in 1820 discovered the relation between electricity and magnetism which states that “when current flows in a straight conductor, a magnetic field is produced in it. The polarity and density of the magnetic field depends on the direction and amount of current flowing through the conductor”. The polarity of a solenoid can also be found by using the Clock rule (also known as the End rule of magnetism). Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Right-hand rule It reveals a connection between the current and the magnetic field lines in the magnetic field that the current created. Ampère was inspired by fellow physicist Hans Christian Ørsted, who observed that needles swirled when in the proximity of an electric current-carrying wire and concluded that electricity could create magnetic fields. In simple words, a current carrying conductor creates a magnetic field around it. The lines of magnetic flux are in the shape of concentric circles and perpendicular on the conductor (at right angle of 90o) as shown in fig. The direction of current and magnetic field can be found by the following rules i.e. right hand gripping rule, the end rule, corkscrew rule, Fleming’s left and right hand rules etc. If the curling motion of the fingers represents a movement from the first (x-axis) to the second (y-axis), then the third (z-axis) can point along either thumb. A cross product, or vector product, is created when an ordered operation is performed on two vectors, a and b. The cross product of vectors a and b, is perpendicular to both a and b and is normal to the plane that contains it. Since there are two possible directions for a cross product, the right hand rule should be used to determine the direction of the cross product vector. 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. 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. 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. Although these currents are moving in opposite directions, a single magnetic force is observed acting on the wire. Therefore, the force occurs in the same direction whether we consider the flow of positive or negative charge carriers in the above image. Applying the right hand rule to the direction of the conventional current indicates the direction of the magnetic force to be pointed right. When we consider the flow of negative charge carriers in the above image, the right hand rule indicates the direction of the force to be left; however, the negative sign reverses the result, indicating that the direction of the magnetic force is indeed pointing right. Activity 3 – Right hand grip rule 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. The relation between current and magnetic field is shown in the following fig using cork screw rule. The direction of flux lines of magnetic field, motion of the conductor and induced EMF and current can be found by Fleming’s left hand and right hand rules which we have discussed in the previous post. The right hand grip rule is especially useful for solving problems that consider a current-carrying wire or solenoid. In both situations, the right hand grip rule is applied to two applications of Ampere’s circuital law, which relates the integrated magnetic field around a closed loop to the electric current passing through the plane of the closed loop.