field of view

Examples of field of view in the following topics:

• Resolution of the Human Eye

  • A model of the human eye can be seen in .
  • The retina of human eye has a static contrast ratio of around 100:1 (about 6.5 f-stops).
  • The approximate field of view of an individual human eye is 95° away from the nose, 75° downward, 60° toward the nose, and 60° upward, allowing humans to have an almost 180-degree forward-facing horizontal field of view.
  • With eyeball rotation of about 90° (head rotation excluded, peripheral vision included), horizontal field of view is as high as 170°.
  • Describe field of view and color sensitivity of the human eye

• Energy Stored in a Magnetic Field

  • A simple generator uses inductance to create a current by the rotation of a magnet within a coil of wire.
  • Therefore, the energy density $u_B = energy / volume$ of a magnetic field B is written as $u_B = \frac{B^2}{2\mu}$.
  • Magnetic field created by a solenoid (cross-sectional view) described using field lines.
  • Energy is "stored" in the magnetic field.
  • Describe behavior of an inductor when the current is changed, and express energy stored in a magnetic field in a form of equation

• Energy in a Magnetic Field

  • Energy is needed to generate a magnetic field both to work against the electric field that a changing magnetic field creates and to change the magnetization of any material within the magnetic field.
  • Energy density is the amount of energy stored in a given system or region of space per unit volume.
  • In general, the incremental amount of work per unit volume δW needed to cause a small change of magnetic field δB is:
  • Magnetic field created by a solenoid (cross-sectional view) described using field lines.
  • Express the energy density of a magnetic field in a form of equation

• Polarization

  • The concept of polarity is very broad and can be applied to molecules, light, and electric fields.
  • For the purposes of this atom, we focus on its meaning in the context of what is known as dielectric polarization—the separation of charges in materials.
  • A dielectric is an insulator that can be polarized by an electric field, meaning that it is a material in which charge does not flow freely, but in the presence of an electric field it can shift its charge distribution.
  • The most basic view of dielectrics involves considering their charged components: protons and electrons.
  • When an electric field (E) is applied, electrons drift away from the field.

• A Quantitative Interpretation of Motional EMF

  • Since the rate of change of the magnetic flux passing through the loop is $B\frac{dA}{dt}$(A: area of the loop that magnetic field pass through), the induced EMF $\varepsilon_{induced} = BLv$ (Eq. 2).
  • The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion.
  • But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet.
  • The direction of the magnetic field is into the screen.
  • Formulate two views that are applied to calculate the electromotive force

• Magnetic Field Lines

  • A pictorial representation of magnetic field lines is very useful in visualizing the strength and direction of the magnetic field .
  • The direction of the magnetic field at any point is parallel to the direction of nearby field lines, and the local density of field lines can be made proportional to its strength.
  • For example, the number of field lines through a given surface is the surface integral of the magnetic field .
  • The strength of the field is proportional to the closeness of the lines.
  • Relate the strength of the magnetic field with the density of the magnetic field lines

• Enhancement of Microscopy

  • Microscopy helps us view objects that cannot be seen with the naked eye.
  • Microscopes are used to view objects that cannot be seen with the naked eye.
  • Bright field: This technique increases the contrast by illuminating the surface on which the objects sit from below.
  • Dark field: This technique is good for improving the contrast of transparent objects.
  • Scanning electron microscope (SEM): The SEM shows details on the surface of a specimen and produces a three-dimensional view by scanning the specimen. shows an SEM image of pollen.

• Paramagnetism and Diamagnetism

  • Paramagnetism is the attraction of material while in a magnetic field, and diamagnetism is the repulsion of magnetic fields.
  • Paramagnetism is a form of magnetism whereby the paramagnetic material is only attracted when in the presence of an externally applied magnetic field.
  • Constituent atoms or molecules of paramagnetic materials have permanent magnetic moments (dipoles), even in the absence of an applied field.
  • When a magnetic field is applied, the dipoles will tend to align with the applied field, resulting in a net magnetic moment in the direction of the applied field.
  • Even in the presence of the field there is only a small induced magnetization because only a small fraction of the spins will be oriented by the field.

• Electric Field Lines: Multiple Charges

  • Electric fields created by multiple charges interact as do any other type of vector field; their forces can be summed.
  • When modeling the electric fields of multiple charges, it's important to take into consideration the sign and magnitude of each charge.
  • For example, the number field of lines should be proportional to the value of the charge that gives rise to them.
  • The strength of the electric field depends proportionally upon the separation of the field lines.
  • As vector fields, electric fields exhibit properties typical of vectors and thus can be added to one another at any point of interest.

• Helical Motion

  • In the section on circular motion we described the motion of a charged particle with the magnetic field vector aligned perpendicular to the velocity of the particle.
  • Then we consider only the component of v that is perpendicular to the field when making our calculations, so that the equations of motion become:
  • The component of the velocity parallel to the field is unaffected, since the magnetic force is zero for motion parallel to the field.
  • If field strength increases in the direction of motion, the field will exert a force to slow the charges (and even reverse their direction), forming a kind of magnetic mirror.
  • Describe conditions that lead to the helical motion of a charged particle in the magnetic field