Fleming’s Left Hand Rule And Right Hand Rule

When a current-carrying conductor is kept in a magnetic field, a force operates on it. The direction of the force may be determined using Fleming's Left-Hand Rule. Similarly, if a moving conductor is placed in a magnetic field, an electric current is induced in that conductor. Fleming's Right-Hand Rule can be utilized to determine the direction of the induced current. It is crucial to note that these rules do not define magnitude; rather, they reveal the direction of the three parameters (magnetic field, current, and force) when the direction of the other two parameters is known. Fleming's Left-Hand Rule is largely relevant to electric motors, whereas Fleming's Right-Hand Rule is primarily applicable to hydraulic motors.

What does Fleming's Right-Hand Rule entail?

When a moving conductor is put inside a magnetic field, a current is induced in it, according to Faraday's law of electromagnetic induction. There will be a connection between the direction of applied force, magnetic field, and current if the conductor is pushed forcibly inside the magnetic field. This relationship between these three directions is determined by Fleming's right-hand rule. "Hold the forefinger, middle finger, and thumb of your right hand at right angles to each other. If the forefinger represents the magnetic field, the thumb represents motion or applied force, and the middle finger represents the induced current," explains the author.

What is the Left-Hand Rule, according to Fleming?

When a current-carrying conductor is exposed to an external magnetic field, it is subjected to a force that is perpendicular to both the field and the direction of the current flow. A left hand can be used to depict three mutually orthogonal axes on the thumb, forefinger, and middle finger, as illustrated in the picture.
"Hold your left hand out in front of you with the forefinger, second finger, and thumb perpendicular to each other. If the field is represented by the forefinger and the current is represented by the second finger, the force is represented by the thumb."

The left hand fulfils the Motor, while the right hand satisfies the Generator. The left-hand rule and the right-hand rule are two visual mnemonics created by Fleming (mnemonics are learning techniques or memory aids, such as rhyme, an abbreviation, or mental image that helps to remember something). In reality, these principles are only employed to identify the direction of the consequent – either current or push – as a convenient gimmick. The Lorentz' Force determines the amount of force along the direction defined by these laws.

Q1. What will be the direction of the force exerted on the proton if the proton travels towards the east after entering a uniform magnetic field in the downward direction?
A: Fleming's Left-Hand Rule is the answer. The direction of the force exerted on the proton may be determined using Fleming's left-hand rule. Because the proton is travelling towards the east, the current is also flowing towards the east. Because the magnetic field is acting downwards, the force is directed towards the north. As a result, we may say that the force is acting in a northerly direction.

Q2. If an electron is travelling vertically upwards and is deflected to the south by a uniform magnetic field, what will be the direction of magnetic field?
A: Fleming's Left-Hand Rule is the answer. We may calculate the direction of the magnetic field acting on the electron using Fleming's left-hand rule. We know that an electron carries a negative charge. When an electron goes upward, the current flows in the opposite direction; that is, the current flows downward. The force exerted on the electron is assumed to be in the south direction. As a result, the magnetic field is oriented towards the east.