Properties of a Force Field
(i) Properties of Gravitational Field
(a) The lines of force are directed towards the centre of the planet; hence, it is a radial field.
(b) The gravitational force field (field strength) ‘g’ at a point is the force per unit mass placed at that point. i.e, g=Fm in N/kg but the S.I unit is m/s2
(c) Any force acting on a body falling towards the centre of the earth is given by F = mg
(d) Gravitational field is a vector quantity.
(ii) Properties of Magnetic Field
(a) Direction: When a magnet is freely suspended, it comes to rest in the South-North direction of the earth.
(b) Attraction: A magnet has the ability to attract magnetic materials e.g, steel, iron, etc.
(c) Force: A magnet exerts force on other magnets in such a manner that like poles repel and unlike poles attract.
(d) The inseparable nature of poles on the magnetic dipoles: If a magnet is broken into small pieces, however small it may be, it will still have a North and South Poles. The smallest bit of a magnet is a dipole.
(e) Magnetic lines of force originate from the North pole and terminate at the South pole.
(iii) Properties of Electric Field
(a) Electric lines of force originate from a positive charge and terminate in a negative charge.
(b) Electric lines of force never cross each other.
(c) They repel each other side ways.
(c) They are in a state of tension which tends to shorten them.
(d) The electric field at a point is defined as the force per unit charge placed at that point. i.e, ε=Fq measured in Newton per Coulomb N/C
- State two properties each of the three vector fields discussed.
- What is the direction of the magnetic lines of force?
- What is the unit of electric field strength?
- Discuss the properties of the magnetic flux.
- Define the electric field strength.
- Itemise the three vector fields.
- Why is electric When a field is represented by lines of force, it is then calledlines of force a vector quantity?