Why is a piece if iron attracted to either pole of a magnet?

Question 20

The magnetic poles of the earth are called geomagnetic poles. Is the north geomagnetic pole a north magnetic pole or a south magnetic pole?

Question 29

When a wire loop is rotated in a magnetic field, the direction of the current induced in the loop reverses itself twice per rotation. Why?

Question 45

? Discuss the relationship between electricity and magnetism
? Identify a device that utilizes the relationship between electricity and magnetism
? Explain how the device you identified uses electricity and magnetism
? Discuss how improvements in electrical conduction and/or advancements in magnets might impact the device you identified
Questions 1

What differences can you think of between the photon and electron?

Question 27

The Bohr Theory permits us to visualize the structure of the atom, whereas quantum mechanics is very complex and concerned with such ideas as wave functions and probabilities. What reasons would lead to the replacement of the Bohr Theory by quantum mechanics?

Question 28

What physical quantities are governed by the quantum numbers of an atomic electron?

The Bohr atom derived from de Broglie'.r relation. Here is another development of Bohr's results for hydrogen. based directly onthe de Broglie relation. If a de Broglie wavelength can be associated with an electron in orbit. then it seems reasonable to suppose that the circumference of an orbit be equal to an integral number of

Calculate the classical frequency for the light emitted by an atom. To do so, note that the frequency of revolution is v/2pir, where r is the Bohr radius. Show that as n approches infinity in
f= 2pi2mk2e4/h3 times 2n-1/(n-a)2 n2
the expression varies as 1/n3 and reduces to the classical frequency.

The answers to this question do not need to be very extensive. A paragraph is more then enough.
1. The first part of the argument questions "Why don't we see things left behind by the Earth as it spins and travels around the sun?" For example, why does a ball dropped from the top of a high tower fall to the base of the tower

The records of Midwestern University show that in one semester, 38% of the students failed mathematics, 27% of the students failed physics, and 9% of the students failed mathematics and physics. A student is selected at random.
a.) If a student failed physics, what is the probability that he or she failed mathematics?
b.)

I need some help with these question:
Two long, straight wires are oriented perpendicular to the computer screen, as shown below, in which L = 4.5 cm. The current in one wire is I1 = 3.1 A, pointing into the screen, and the current in the other wire is I2 = 4.0 A, pointing out of the screen. Find the magnitude and direction of

See the attached file.
3.) A head is (approximately) a conducting sphere of radius 10 cm. What is the capacitance of the head? What will be the charge on the head if, by means of a Van De Graaf generator, you raise the potential on the head to 100,000 V?
What voltage would be required to cause electrostatic break down in ai

Please provide some assistance with the following problem on transformers. Please discuss the mode of action of a transformer, step-up vs step-down transformers and the number of turns in the primary winding. Please view the attachment file for the full problem and figure.

1.) In a Rutherford scattering experiment, an α-particle (charge = +2e) heads directly toward a gold nucleus (charge = +79 e). The -particle had a kinetic energy of 4.9 MeV when very far (r -> ∞ ) from the nucleus. Assuming the gold nucleus to be fixed in space, determine the distance of closest approach. (Hint: Use c