Magnetism and Electromagnetism Online Test – Multiple Choice Questions and Answers 1. The motional e.m.f. induced in a coil is independent of resistance number of turns change of flux time 2. The unit of flux density is known as a weber magnetomotive force a tesla a maxwell 3. What is the reluctance of a material that has a length of 0.045 m, a cross-sectional area of 0.015 m2 , and a permeability of 2500 µWb/At·m? 1200 At/Wb 0.27 At/Wb 833.33 µAt/Wb More information is needed in order to find the reluctance 4. How much flux is there in a magnetic field when its flux density is 5000 mu.gifT and its cross-sectional area is 300 mm²? 16.67 mWb 5.0 µWb 1.5 µWb 3.0 mWb 5. If positively charged particles enter with high velocity from the sky towards the earth, then the earths magnetic field will deflect them towards west east south north 6. The direction of induced current is given by? Ampere’s Law Snell’s law Lenz’s Law Faraday’s Law 7. A Hall effect sensor exists only in theory produces very large voltages can operate only a few times before failure is a noncontacting magnetic sensor 8. The energy resides in a current carrying conductor in the form of magnetic field both electrostatic field and thermal vibration electrostatic field thermal vibration 9. Permeability is the inverse equivalent of which electrical term? Current Voltage Resistance Conductance 10. What is the magnetomotive force in a 150-turn coil of wire with 2 A flowing through it? 300 At 152 At 13.33 mAt 75 At Loading … Question 1 of 10
