312315 Elements of Electrical Engineering Manual Practical No 1 Answer
 |
| 312315 Elements of Electrical Engineering Manual Answer |
Practical Significance:
In industries measurements of static and dynamic EMF with utmost accuracy and precision is a prime requirement. Such kinds of measurements are possible using measuring instruments like voltmeters, ammeters, etc. In this practical, we use a voltmeter, and an ammeter to measure the static-induced emf.
Procedure
1. Connect two ends of the coil to the Galvanometer.
2. Take a bar magnet of known polarity.
3. Move the bar magnet in the coil as per the sequence given in the observation table.
4. Observe the deflection of the Galvanometer.
Observation table for statically induced emf
| S.N. | Movement of Bar Magnet | Movement of the Magnet | Deflection of Galvanometer connected across the coil |
|---|---|---|---|
| 1 | Towards the coil | Slow | Forward (Less) |
| 2 | Towards the coil | Fast | Forward (More) |
| 3 | Away from the coil | Slow | Reverse (Less) |
| 4 | Away from the coil | Fast | Reverse (More) |
Observation table for dynamically induced emf
| S.N. | Position of the Magnet | Movement of the Magnet | Deflection of Galvanometer connected across the coil |
|---|---|---|---|
| 1 | N-Pole towards the coil | Slow | Forward (Less) |
| 2 | N-Pole towards the coil | Fast | Forward (More) |
| 3 | S-Pole towards the coil | Slow | Forward (Less) |
| 4 | S-Pole towards the coil | Fast | Forward (More) |
Practical related questions
1. Define magnetic flux.
Answer:
Magnetic flux measures the overall magnetic field passing through a specific area, making it a valuable tool for explaining how the magnetic force affects objects within that area. The measurement of magnetic flux is dependent on the specific area selected.
2. Define flux linkages.
Answer:
The flux linkage is a property of the conducting coil and the magnetic field it passes through. It is determined by the number of turns in the coil and the magnetic field's flux. The flux linkage is defined as the total flux that passes through a surface created by a closed conducting loop, with its direction being perpendicular to the surface. It is represented by the symbol lambda and is equal to NBA, where B represents the magnetic field, A represents the surface area, and N represents the number of turns in the coil.
3. State Faraday‟s laws of electromagnetic induction.
Answer:
First law: It states that whenever there is a change in magnetic flux associated with a coil, EMF is induced in that coil.
Second law: It states that the magnitude of EMF induced in the coil is directly proportional to the rate of change of magnetic flux associated with that coil.
4. State Lenz‟s law.
Answer:
Lenz's law states that the current induced in a circuit due to a change or a motion in a magnetic field is so directed as to oppose the change in flux and to exert a mechanical force opposing the motion.
5. State Fleming‟s Right Hand Rule
Answer: Fleming′s Right hand rule shows the direction of induced current when a conductor attached to a circuit moves in a magnetic field.
- The thumb is pointed in the direction of the motion of the conductor relative to the magnetic field.
- The first finger is pointed in the direction of the magnetic field.
- Then the second finger represents the direction of the induced current.