AP® Physics 1 & 2

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Transformer and Battery


A large electromagnetic transformer that is used for classroom demonstrations involves two coils of wire wrapped around opposite sides of a solid iron core. When the primary coil, with terminals A and B, is connected to a 9-volt AC power source, the light bulb in the secondary other coil seems to glow with constant brightness.

If terminals A and B were instead connected to a 9-volt battery, then the light bulb would


glow with much brighter and constant intensity.


at first glow bright, but then slowly fade until it was not glowing at all.


flash bright at the instant the terminals are connected, but then not glow at all.


never glow.