control rod

Examples of control rod in the following topics:

• Nuclear Fission in Reactors

  • A nuclear chain reaction can be controlled by using neutron poisons and neutron moderators to change the percentage of neutrons that will go on to cause more fissions.
  • The power output of the reactor is adjusted by controlling how many neutrons are able to create more fissions.
  • Control rods that are made of a neutron poison are used to absorb neutrons.
  • Absorbing more neutrons in a control rod means that there are fewer neutrons available to cause fission, so pushing the control rod deeper into the reactor will reduce the reactor's power output, and extracting the control rod will increase it.

• Mechanical Work and Electrical Energy

  • where B is the magnetic field, l is the length of the conducting rod, and v is the (constant) speed of its motion.
  • As the rod moves and carries current i, it will feel the Lorentz force
  • To keep the rod moving at a constant speed v, we must constantly apply an external force Fext (equal to magnitude of FL and opposite in its direction) to the rod along its motion.
  • Since the rod is moving at v, the power P delivered by the external force would be:
  • Right hand rule gives the current direction shown, and the polarity of the rod will drive such a current.

• Motional EMF

  • Consider the area enclosed by the moving rod, rails and resistor.
  • B is perpendicular to this area, and the area is increasing as the rod moves.
  • Thus the magnetic flux enclosed by the rails, rod and resistor is increasing.
  • Note that the area swept out by the rod is ΔA=ℓx.
  • Right hand rule gives the current direction shown, and the polarity of the rod will drive such a current.

• The Physical Pendulum

  • Recall that a simple pendulum consists of a mass suspended from a massless string or rod on a frictionless pivot.
  • In that case, we are able to neglect any effect from the string or rod itself.
  • For illustration, let us consider a uniform rigid rod, pivoted from a frame as shown (see ).
  • The moment of inertia of the rigid rod about its center is:
  • A rigid rod with uniform mass distribution hangs from a pivot point.

• Elasticity, Stress, and Strain

  • Additionally, the change in length is proportional to the original length L0 and inversely proportional to the cross-sectional area of the wire or rod.
  • Tension: The rod is stretched a length ΔL when a force is applied parallel to its length.
  • (b) Compression: The same rod is compressed by forces with the same magnitude in the opposite direction.
  • For larger deformations, the cross-sectional area changes as the rod is compressed or stretched.

• Stress and Strain

  • Tension: The rod is stretched a length $\Delta L$ when a force is applied parallel to its length.
  • (b) Compression: The same rod is compressed by forces with the same magnitude in the opposite direction.
  • For larger deformations, the cross-sectional area changes as the rod is compressed or stretched.

• Length Contraction

  • Let's look at the results with the aether again.If we have a rod of length $L_0$ in the primed frame what it is length in the unprimed frame.

• Trigonometry

  • A rod 'AB' is hinged at 'A' from a wall and is held still with the help of a string, as shown in .
  • The rod is hinged from a wall and is held with the help of a string.

• Conductors and Fields in Static Equilibrium

  • For example, if a neutral conductor comes into contact with a rod containing a negative charge, some of that negative charge will transfer to the conductor at the point of contact.

• Fracture

  • Weight-bearing structures have special features; columns in building have steel-reinforcing rods while trees and bones are fibrous.