Old Dominion University PHYS 112N Phys 112_ lab 7 Magnetic Induction.

Introduction:

This experiment has two major objectives that are being shown here. The first one is to
see how a changing magnetic field can induce a current in a circuit. The second one is to test
how both step-up and step-down transformers work and how iron can induce emf. Along with
these objectives some major theories are being tested here such as magnetic induction and
transformers. Magnetic induction is when a magnet is passed through a coil, there is a change in
the magnetic flux through the coil which induces an emf in the coil. This is essentially what
Faraday’s Law of Induction: ε=-N Δϕ
Δt . Transformers are used to increase or decrease AC
voltages which was explored in part B of this experiment. Once everything has been set up
according to the lab manual, part A is Magnet Induction. This is where the magnets were placed
into and around the coil to see how and which magnet would give the most induced emf. Once
this has been done part B is to set up a step-down transformer. Start with the iron core removed
from the coils and with the small coil outside of the large coil. Follow the steps provided for the
program and get it running in the lab manual. Then insert the small coil into the larger and
observe the signal. Get the maximum voltage for the primary and secondary. These same steps
will be repeated for the step-up transformer once the set up for it has been done.
Data and Data Analysis: