Curriculum
- 25 Sections
- 92 Lessons
- 70 Hours
- 1.1 - Physical quantities and measurement techniques5
- 1.1Use of rulers and measuring cylinders to find a length or a volume
- 1.2Describe how to measure a variety of time intervals using clocks and digital timers
- 1.3Determine an average value for a small distance and for a short interval of time by measuring multiples (including the period of oscillation of a pendulum)
- 1.4Quiz Test 1Copy10 Minutes2 Questions
- 1.5TestCopy
- 1.2 - Motion4
- 1.3 - Mass and weight1
- 1.4 - Density1
- 1.5 - Forces5
- 1.6 - Momentum1
- 1.7 - Energy, work and power5
- 1.8 - Pressure1
- 2.1 - Kinetic particle model of matter5
- 2.2 - Thermal properties and temperature5
- 2.3 - Transfer of thermal energy5
- 3.1 - General properties of waves6
- 3.2 - Light7
- 3.3 - Electromagnetic spectrum2
- 3.4 - Sound3
- 4.1 - Simple phenomenon of magnetism3
- 4.2 - Electrical quantities5
- 4.3 - Electric circuits7
- 18.1Circuit diagram – Circuit components and their functionsCopy
- 18.2Effective or equivalent resistance in series and parallel circuitsCopy
- 18.3Behaviour of series and parallel circuitsCopy
- 18.4Function of LDR (Light Dependent Resistor) and thermistorCopy
- 18.5Potential divider and potentiometerCopy
- 18.6Use of relay in a circuitCopy
- 18.7Diode in half and full wave rectifier bridgeCopy
- 4.4 - Electrical safety2
- 4.5 - Electromagnetic effects6
- 5.1 - The nuclear model of the atom2
- 5.2 - Radioactivity5
- 6.1 - Earth and the Solar System2
- 6.2 - Stars and the Universe3
- Paper 6 instructions3
The magnetic effect of a currentCopy
Learning Objectives
- Describe the pattern of the magnetic field (including direction) due to currents in straight wires and in solenoids
- Describe applications of the magnetic effect of current, including the action of a relay
- State the qualitative variation of the strength of the magnetic field over salient parts of the pattern
- State that the direction of a magnetic field line at a point is the direction of the force on the N pole of a magnet at that point
- Describe the effect on the magnetic field of changing the magnitude and direction of the current
Contents to learn
Magnetic field around a current carrying conductor
Whenever electric current passes through the conductor, magnetic field establishes around it.
Direction of magnetic field around the current carrying can be determined by using Right Hand Grip Rule.
Magnetic field around straight current carrying conductor
When electric current passes through the straight current carrying conductor, magnetic field establishes around it. Direction of magnetic around straight current carrying conductor can be determined by using Right Hand Grip Rule.
Keep thumb of your right hand in the direction of the electric current. Curled fingers will give you the direction of the magnetic field, which may be clockwise or anticlockwise. In the above diagram, direction of the magnetic field is anticlockwise, when the current is in teh upward direction.
If the direction of the electric current will be reversed (means downward), the direction of the magnetic field will also be reversed (means clockwise).
Magnetic field around a current carrying solenoid
A solenoid is tightly wound conducting wire of cylindrical shape. It has many circular loops or turns of same diameter, wound side by side or one over another.
When current is passed through a solenoid the direction of current in all of its turns would be same i.e. clockwise or anti-clockwise. So magnetic field due to current in neighboring turns will support one another. As result the magnetic field inside solenoid is very strong and is comparatively weak outside it.
According to Right Hand Grip rule (in case of solenoid), curl figures of your right hand in the direction of the electric current, thumb will point the north pole of the magnetic field.
From one end of solenoid the current will appear anticlockwise, so this end will act north pole and magnetic field lines will come out of solenoid from this end. From other end of solenoid current will appear clockwise. So this end will act as south pole and magnetic field lines will enter solenoid through this end.
Inside the solenoid the magnetic field lines from one end to other will be almost parallel to one another. So the magnetic field inside a long solenoid is not only strong but uniform also.
It is similar to magnetic field of a bar magnet. The strength of magnetic field inside a solenoid depends upon the current in solenoid and number of turns per unit length of it. It also depends upon the medium inside the solenoid.
