State Fleming’s left hand rule.
Answers
Explanation:
Fleming's left-hand rule states that “When a current-carrying conductor is placed in an external magnetic field, the conductor experiences a force perpendicular to both the field and to the direction of the current flow.” It was invented by John Ambrose Fleming.
Fleming's Left Hand Rule :
Fleming's left-hand rule for electric motors is one of a pair of visual mnemonics, the other being Fleming's right-hand rule[1] (for generators). They were originated by John Ambrose Fleming, in the late 19th century, as a simple way of working out the direction of motion in an electric motor, or the direction of electric current in an electric generator.
When current flows through a conducting wire, and an external magnetic field is applied across that flow, the conducting wire experiences a force perpendicular both to that field and to the direction of the current flow (i.e they are mutually perpendicular). A left hand can be held, as shown in the illustration, so as to represent three mutually orthogonal axes on the thumb, fore finger and middle finger. Each finger is then assigned to a quantity (mechanical force, magnetic field and electric current). The right and left hand are used for generators and motors respectively.
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When a current-carrying conductor is placed under a magnetic field, a force acts on the conductor. The direction of this force can be identified using Fleming’s Left Hand Rule. Likewise, if a moving conductor is brought under a magnetic field, electric current will be induced in that conductor. The direction of the induced current can be found using Fleming’s Right Hand Rule. It is important to note that these rules do not determine the magnitude, instead show only the direction of the three parameters (magnetic field, current, force) when the direction of the other two parameters is known.