Magnetic Effects of Current MCQ Test 1 1. The magnetic intensity at the centre of a circular coil (radius) carrying a current of 1 ampere is proportional to . (a) r (b) r –1 (c) r–2 (d) r+2 2. The unit of B in SI system is . (a) T (b) Wb-m2 (c) N-A-m2 (d) N-A–1m–2 3. Two wires, carrying equal currents in the same direction, placed one can apart experience: (a) an attractive force (b) a repulsive force (c) sometime an attractive an sometimes a repulsive force (d) no force at all 4. Each of the two long straight parallel wires of negligible cross section placed in vacuum at a distance of 1 metre from each other carries a current of 2 ampers. The force per unit length between the wire is : (a) 1 x 10–7 Newton (b) 2 x 10–7 Newton (c) 4 x 10–7 Newton (d) 8 x 10–7 Newton 5. An electron enters a region of uniform magnetic field with a certain velocity in the direction of the filed. It will move: (a) along the direction of the filed with unchanged velocity (b) along the direction on filed with decreasing velocity (c) along the direction of filed with increasing velocity (d) in a circle with constant speed 6. If m are e are the mass and charge of a particle being accelerated in a cyclotron having magnetic field B, than the time for half a rotation of the particle is : (a) eB/mπ (b) mB/eπ (c) πm/eB (d) m/πeB 7. The tangent galvanometer is called so because: (a) It was invented by Tangent (b) It remain tangential to earth’s surface (c) It produced a magnetic field tangential to the graduated circle (d) it works on he principle of tangent law 8. The magnet used in a tangent galvanometer is kept small because: (a) otherwise the two poles would not be equal strength (b) otherwise the galvanometer would be more susceptible to outside disturbance (c) otherwise a very large current would be required to move the needle and this would damage the coil (d) the magnetic field produced by the coil would not be appreciably constant over the dimension of the magnet so that the tangent law would not apply well 9. Which of the following statements is applicable to a ballistic galvanometer? (a) damping is small but its time period is large (b) damping as well as its time period are small (c) damping and its time period both are large (d) damping is large but is time period is small 10. If a bar magnet of length gives null point of distance d1 in Tan A and d2 in Tan B position, then: (a) (d1/d2)sq1/2=2 (b) d1/d2 = 2 (c) (d1/d2)sq2 = 2 (d) (d1/d2)sq3 = 2 Answer Keys: 1. (b) 2. (a) 3. (a) 4. (d) 5. (a) 6. (c) 7. (d) 8. (d) 9. (b) 10. (d)
Posted on: Thu, 20 Jun 2013 17:25:37 +0000
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