Magnetostatics Objectives Part 08

141 . The magnetic force in the air gap will be 15000At/m

142 . The number of ampere turns required to produce that flux is 159AT

143 . Diagram Question—

144 . The correct relation is 1Ampere-turn =4pi Gilberts

145 . The magnetizing force on an iron ring is 1750 AT/m when the flux density is 1.1 T. The relative permeability if iron is 500

146 . The quickest and the most effective way of making a magnet from soft iron is by placing it inside a coil carrying current

147 . Hard magnet materials are used for making permanent magnets

148 . A material commonly used for shielding or screening magnetism is soft iron

149 . A keeper is used to provide a closed path for flux

150 . In electrical circuits, resistance is to current is the same as in magnetic circuits reluctance is to coercivity

151 . The lagging of flux density behind the applied magnetizing force is known as hysteresis

152 . Reluctance: Inductance:: AT/Weber : Henry
Questions 153 and 154 refer to data given below:
Two conductors A and B are insulated from each other and contained within a single electric cable. Conductor A has a current of 25A while the current in conductor B is 9.5A. A 15cm length of the electric cable is situated within a magnetic field at right angles to the field. The flux density of the field is 0.85T

153 . The force on the cable, when the conductor currents are in the same direction, will be 4.4N

154 . The force on the cable, when the conductor currents are on the opposite directions, will be 2N

155 . A 0.5mm air gap has a cross-sectional area of 7cm2. The mmf required to generate a total flux of 50 microWb in the air gap 28.4A