Exam 3 problems
... the penetration depth. What limit does this place on the frequency (in Hz) of the field variation for a metal such as gold if the quasistatic approximation is to be valid? What is the shortest wavelength? 2. Show thatt = Re[(c/4) (1/2) E x H*] for periodically varying fields.
3. Show that for f ...
... the penetration depth. What limit does this place on the frequency (in Hz) of the field variation for a metal such as gold if the quasistatic approximation is to be valid? What is the shortest wavelength? 2. Show that
Braking Index of Isolated Pulsars
... Given that the most accurately measured braking indices are for “slow” rotation, and span a range of values from 1 ~ 2.8, it may be interesting to consider a braking index which may be a combination of more than one mechanism. Expand the braking law by a polynomial: Ω̇=−s (t)Ω−r (t)Ω3−g (t )Ω5 ...
... Given that the most accurately measured braking indices are for “slow” rotation, and span a range of values from 1 ~ 2.8, it may be interesting to consider a braking index which may be a combination of more than one mechanism. Expand the braking law by a polynomial: Ω̇=−s (t)Ω−r (t)Ω3−g (t )Ω5 ...
20-6 Electric Generators
... Answer to Essential Question 20.5: For the region that is moving out of the field, the After picture shows fewer field lines passing through the region than the Before picture does (see Figure 20.29). The To Oppose picture shows a field line directed into Figure 20.29: The pictorial method the page, ...
... Answer to Essential Question 20.5: For the region that is moving out of the field, the After picture shows fewer field lines passing through the region than the Before picture does (see Figure 20.29). The To Oppose picture shows a field line directed into Figure 20.29: The pictorial method the page, ...
induced magnetic field - Southwest High School
... about 120,000 volts or more, stepped down to 2400 volts in the city, and finally stepped down again by a transformer to provide the 120 (240) volts used in household circuits. ...
... about 120,000 volts or more, stepped down to 2400 volts in the city, and finally stepped down again by a transformer to provide the 120 (240) volts used in household circuits. ...
Force between magnets
Magnets exert forces and torques on each other due to the complex rules of electromagnetism. The forces of attraction field of magnets are due to microscopic currents of electrically charged electrons orbiting nuclei and the intrinsic magnetism of fundamental particles (such as electrons) that make up the material. Both of these are modeled quite well as tiny loops of current called magnetic dipoles that produce their own magnetic field and are affected by external magnetic fields. The most elementary force between magnets, therefore, is the magnetic dipole–dipole interaction. If all of the magnetic dipoles that make up two magnets are known then the net force on both magnets can be determined by summing up all these interactions between the dipoles of the first magnet and that of the second.It is always more convenient to model the force between two magnets as being due to forces between magnetic poles having magnetic charges 'smeared' over them. Such a model fails to account for many important properties of magnetism such as the relationship between angular momentum and magnetic dipoles. Further, magnetic charge does not exist. This model works quite well, though, in predicting the forces between simple magnets where good models of how the 'magnetic charge' is distributed is available.