Which applies where a constant area of loop is within a changing magnetic field. Where □ is the number of turns of the coil, □ is the magnetic field strength, and Δ □ Δ □ is the rate of change of the area of the coil perpendicular to the magnetic field that is entering the magnetic field. The emf, □, induced across a coil entering a magnetic field is given by the formula The emf induced has a sign as well as a magnitude.įormula: Emf Induced in a Current Loop due to a Changing Magnetic Field The formula for the magnitude of □ is not the complete version of the formula. Substituting the values of □ and Δ □ we have determined,Ġ. The time, □, for which the coil moves is given by The speed of the coil is stated to be 7.5 cm/s, or 0.075 m/s. The coil moves a distance of 1.5 cm, or 0.015 m. This gives a value of □ of 12.5 cm, or 0.125 m. The value of □ is not given, but this is equal to half of the diameter, □, of the coil. The emf induced is stated to be 3.6 mV, or 0.0036 V. To determine Δ □, the equation must be rearranged to make Δ □ the subject, as follows: We wish to determine the magnitude of Δ □. In this form of the equation, □ is constant and a change in □, Δ □, is a term in the equation. We can therefore express the equation for □ as Instead, the magnetic field strength changes. In this case, however, the area of the coil that is within the magnetic field does not change. The magnitude of the emf, □, induced across a coil entering a magnetic field is given by the formula Using the directions of motion and magnetic field for the part of a conducting loop in the coil that first starts to enter the magnetic field, the direction of current in the loop is shown in the following figure. The direction of the current can be determined using the right-hand rule. We can substitute these values into the formula to obtain The time interval in which this happens is stated to be 0.24 s. Half of the area of the coil enters the magnetic field. Where □ is stated to be 13 cm, which equals 0.13 m. The value of □ is stated to be 35, and the value of □ is stated to be 0.16 T. Where □ is the number of turns of the coil, □ is the magnetic field strength, and Δ □ Δ □ is the rate of change of the area of the coil entering the magnetic field. The magnitude of the emf, □, induced across the coil is given by the formula Is the current through the coil clockwise or counterclockwise?.What is the magnitude of the electromotive force induced in the coil? Give your answer to two decimal places.This is shown in the following figure showing the positions at one-second time intervals of two identical loops entering two identical magnetic fields. The rate of change of magnetic flux linkage can be represented by the rate at which a loop passes through the lines of a magnetic field. Where □ is the magnetic field strength in the region and □ is the area perpendicular to the direction of the magnetic field that the magnetic field lines pass through. The magnetic flux, □, in a region of space is given by This is known as the rate of change of magnetic flux linkage. The value of □ depends on the rate at which the magnetic field through a loop changes. This is often referred to as the emf induced in the loop, □. We can therefore define the potential difference induced in a loop by a change of magnetic field. Where □ is the work done by the potential difference on a charge, □, across the potential difference.įor a conducting loop, “across the potential difference” means “around the loop.” When the magnetic field through the loop changes, work is done on free electrons in the loop to move them around the loop against the resistance of the material that the loop is made of. A loop however has no ends, so a different idea of potential difference must be considered.Ī potential difference, □, can be expressed as For a straight conductor, a potential difference is a difference in potential of the ends of the conductor. In addition to the current induced in a loop, it can be useful to consider the potential difference induced in a loop.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |