Physics final Exam #2 Flashcards
Several capacitors are connected in series with a battery. The potential different across each capacitor
adds up to equal the emf of the battery
What does Kirchhoff’s junction law say?
current going in equals current going out
What can RC circuits be used for?
windshield wipers, computer timing, flashing lights on bikes
How can you model cell walls as electric elements?
as capacitors and resistors
When capacitors are connected in series
they have the same charge
Refrigerator magnets
have multiple poles arranged as long U-magnets
How are magnetic force, wire length, current, and magnetic field related?
F=ILB
The force on a moving charged object in a magnetic field is
perpendicular to magnetic field and the object’s velocity
The magnetic field inside a solenoid does not depend on
the radius of the solenoid
Two current-carrying wires parallel to each other exert
repulsive or attractive forces depending on the current’s direction
In order for an electric motor to work
current must change direction every half cycle
Which elements are ferromagnetic?
iron, cobalt, nickel
The induced current due to a changing magnetic flux produces a magnetic field which
opposed the change in flux
The potential difference created by moving a conductor in a magnetic field is called
motional emf
Induced current is current created by
a changing magnetic field
What law describes the directions of eddy currents produced when a conductor moves through a magnetic field?
Lenz’s law
The polarization of electromagnetic waves refers to the orientation of
the electric field
The speed of an electromagnetic wave
is equal to the speed of light
Which part of the electromagnetic spectrum is more particle-like?
x-rays
Which animal has 4 types of cones in their eyes?
chicken
Which parts of the electromagnetic spectrum can ionize molecules and/or atoms?
ultraviolet, x-rays, gamma rays
How does MRI work?
long solenoid, nuclei of atoms have magnetic moments and behave like magnetic dipoles
What are materials that are strongly attracted to magnets/can be magnetized called?
ferromagnetic
When is current induced in a loop of wire?
when flux through the loop changes
