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Motor (left)
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coil in a field becomes a motor if current is fed through a commutator.
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Motor (left)
What is it?
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coil in a field becomes a motor if current is fed through a commutator.
In simple words
Motor (left) is a core idea in this chapter. Learn the meaning first, then the main parts, then one clear example.
Examples
- Loudspeaker coil (named)
- Simple d.c. motor kit
- Force is zero if I is parallel to B
MOTOR (LEFT)
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coil in a field becomes a motor if current is fed through a commutator.
Recommended for Class 10
Full school-level explanation
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coil in a field becomes a motor if current is fed through a commutator.
Two hands, two jobs:
MOTOR (LEFT)
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coil in a field becomes a motor if current is fed through a commutator.
Remember
- F B I L
- commutator in a d.c. motor
Examples
- Loudspeaker coil (named)
- Simple d.c. motor kit
- Force is zero if I is parallel to B
Remember
- F B I L
- commutator in a d.c. motor
- grip for the wire field
- left = motor
- F B I L
- commutator in a d.c. motor
How the ideas connect
A long straight wire: field circles. A solenoid: field like a bar magnet, with a N and S. Increasing turns or current strengthens it. A core of iron concentrates the field (electromagnet, already in Class 9).
Deeper understanding
Go beyond memorising Motor (left). Connect the definition to reasons, relationships, exceptions, and exam wording.
How the ideas connect
A long straight wire: field circles. A solenoid: field like a bar magnet, with a N and S. Increasing turns or current strengthens it. A core of iron concentrates the field (electromagnet, already in Class 9).
Exam focus
Quick revision
- F B I L
- commutator in a d.c. motor
- grip for the wire field
- left = motor
- MOTOR (LEFT): First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic f
- Exam tip: Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL
Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
For long answers on Motor (left): define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- F B I L
- commutator in a d.c. motor
- grip for the wire field
- left = motor
Important formulas
- F B I L
- commutator in a d.c. motor
- grip for the wire field
Common exam traps
- Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
- Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
- Mistake
Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
- Mistake
Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
F B I L
commutator in a d.c. motor
grip for the wire field
left = motor
First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coi
left = motor
- Definition
- First finger Field, seCond finger Current, thuMb Motion. That is the force on a wire in a magnetic field (F = B I L for a school straight wire at 90 deg). A coi
- Formula
- left = motor
- Example
- Loudspeaker coil (named)
- Critical warning
- Left-hand motor, right-hand dynamo. Writing the wrong hand loses the direction mark even if F = BIL is quoted.
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Exam Practice
Define
Q1. Define Motor (left).
Explain
Q2. Explain: MOTOR (LEFT).
Example
Q3. Give one clear example of Motor (left) and say why it fits.
Mistake
Q4. State one common mistake students make about Motor (left).
Exam note
Q5. Write a short exam note on Motor (left): definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.