Any change in the magnetic environment of a coil of wire will cause a voltage to be in the coil. No matter how the change is produced, the voltage will be generated. The change could be produced by changing the magnetic field strength, moving a magnet toward or away from the coil, moving the coil into or out of the magnetic field, rotating the coil relative to the magnet, etc.
V - Voltage generatedB - Magnetic fluxt - TimeA - Area of the coilN - Number of turns
In This Flash animation you can generate voltage and see bulb is glowing by changing the magnetic field strength, to that simply move a magnet toward or away from the coil. You can move magnet by clicking and dragging it using mouse pointer.
Notice on voltmeter, it indicate the direction of the current flow by showing needle moving to plus and minus direction. You can select the show field lines check box to see the magnetic field lines from magnet.