Unit 202 Revision #2

The relationship between the mass of a body (m), the applied force to the body (F) and the acceleration of the body (a) is given by the formula

The SI unit of time is the second. Express 0.00001 seconds in a suitable sub multiple

In a magnetic circuit the magnetic field strength H is expressed in ampere turns/metre. H is calculated using the formula

The formula used to calculate the resistance (R) of a conductor, given its length (l), cross sectional area (a) and the constant of resistivity (r)

A simple alternator consists of a coil which is rotated in a permanent magnetic field.

      The emf generated in the rotating coil is connected to a load via the-

If the input energy and output energy of a machine are known, the percentage efficiency of the machine is calculated using the formula

The most common material used to manufacture brushes used in a.c. and d.c. rotating machines is

The material used as an insulator on which overhead lines are suspended from pylons is

Electric current is the flow of negatively charged particles called

In a domestic battery system linked to a PV installation the emf is produced by