Physics-DPP-4-Magnetism

PHYSICS Topic: Magnetism Date: 1. AB and CD are smooth, parallel, horizontal rails on which a conductor T can slide. A cell, E, drives current i through the rails and T. (a) The current in the rails will set up a magnetic field over T. (b) T will experience a force to the right. (c) T will experience a force to the left. (d) T will not experience any force. 2. In the pervious questions, (a) the force on T is proportional to i. (b) the force on T is proportional to i2. (c) if the direction of i is reversed in the circuit by reversing E, the force on T will reverse in direction. (d) if the direction of i is reversed in the circuit by reversing E, the force on T will remain in the same direction. 3. Two long, thin, parallel conductors, separated by a distance d, carry current i1 and i2. The force acting on unit length of any one conductor is F. (a) F is attractive, if i1 and i2 flow in the same direction. (b) F is attractive, if i1 and i2 flow in opposite directions. (c) F is the same for both conductors. (d) F is different for the two conductors. 4. In the previous question, (a) F  (i i ) (b) F  (i i )2 (c) F µ 1 (d) F µ 1 1 2 1 2 d 2 d 5. AB and CD are smooth parallel rails, separated by a distance l, and inclined to the horizontal at an angle . A uniform magnetic field of magnitude B, directed vertically upwards, exists in the region. EF is a conductor of mass m, carrying a current i. For EF to be in equilibrium, (a) i must flow from E to F (b) Bil = mg tan  (c) Bil = mg sin  (d) Bil = mg PHYSICS Topic: Magnetism Date: 6. In the previous question, if B is normal to the plane of the rails, (a) Bil = mg tan  (b) Bil = mg sin  (c) Bil = mg cos  (d) equilibrium cannot be reached r ur r ur 7. A flat coil carrying a current has a magnetic moment μ . It is placed in a magnetic field B such that μ is antiparallel to B . The coil is (a) Not in equilibrium (b) in stable equilibrium (c) in unstable equilibrium (d) in neutral equilibrium ur uuur r r 8. A conductor AB carries a current i in a magnetic field B . If AB = r and the force on the conductor is F r r r ur (a) F does not depend on the shape of AB (b) F = i (r ´ B) r ur r r r ur (c) F = i(B ´ r) (d) | F |= i( r . B) 9. A semicircular wire of radius r, carrying a current i, is placed in a magnetic field of magnitude B. The force acting on it. (a) Can never be zero (b) Can have the maximum magnitude 2Bir (c) Can have the maximum magnitude Bir (d) Can have the maximum magnitude Bir 10. A flat circular coil, carrying a current, has a magnetic moment . (a)  has only magnitude; it does not have direction. (b) The direction of  is along the normal to the plane of the coil. (c) The direction of  depends on the direction of the current flow. (d) The direction of  does not change if the current in the coil is reversed. PHYSICS Topic: Magnetism Answer Key Date: 1. (a, b) 2. (b, d) 3. (a, c) 4. (a, d) 5. (a, b) 6. (b) 7. (c) 8. (a, b) 9. (b) 10. (b, c)

Comments

Post a Comment

Popular posts from this blog

PHYSICS-15-10- 11th (PQRS) SOLUTION

XI (PQRS) PHYSICS REVIEW TEST-5 Select the correct alternative. (Only one is correct) [15 × 3 = 45] There is NEGATIVE marking. 1 mark will be deducted for each wrong answer. Q.31 Two trains, which are moving along different tracks in opposite directions towards each other, are put on the same track due to a mistake. Their drivers, on noticing the mistake, start slowing down the trains when the trains are 300 m apart. Graphs given below show their velocities as function of time as the trains slow down. The separation between the trains when both have stopped, is: (A) 120 m (B) 280 m (C) 60 m (D*) 20 m 1 [Sol: x1 = 2 1 × 10 × 40 = 200 m; x2 = – 2 × 8 × 20 = –80 m  xreletive = x1 + x2 = 280  separation = 300 – 280 = 20 m (D) ] Q.32 One end of a thin uniform rod of length L and mass M is riveted to the centre of a uniform circular disc of radius r and mass 2 M so that the rod is normal to the disc. The centre of mass of the combination from the centre of the disc is at dist
Read more

8-Circular Motion

8.1 (D) The maximum angular speed of the hoop corresponds to the situation when the bead is just about to slide upwards. The free body diagram of the bead is For the bead not to slide upwards. m2 (r sin 45°) cos 45° – mg sin 45° < N (1) where N = mg cos 45° + m2 (r sin 45º) sin 45° (2) From 1 and 2 we get.  = rad / s. 8.2 (C) Let v be the speed of particle at B, just when it is about to loose contact. From application of Newton's second law to the particle normal to the spherical surface. mv2 = mg sin  (1) r Applying conservation of energy as the block moves from A to B.. 1 mv2 = mg (r cos  – r sin ) (2) 2 Solving 1 and 2 we get 3 sin  = 2 cos  8.3 (A) As the mass is at the verge of slipping ∴ mg sin37 –  mg cos37 = m2r 6 – 8 = 4.5   = 3 16 8.4 (B) As when they collide vt  1  72v 2  2 2  25R   R = vt  t =   5R 6v Now angle covered by A =   vt R 11 Put t  angle covered by A = 6 8.5 (C) The acceleration vector s
Read more

4. THEORY-Current Electrictricity

CURRENT ELECTRICITY  1 . ELECTRIC CURRENT (a) Time rate of flow of charge through a cross sectional area is called Current. if q charge flows in time interval t then average current is given by q Iav = t and Instantaneous current i =. lim q  dq t0 t dt (b) Direction of current is along the direction of flow of positive charge or opposite to the direction of flow of negative charge. But the current is a scalar quantity. i i q+ velocity q– velocity SI unit of current is ampere and 1 Ampere = 1 coloumb/sec 1 coloumb/sec = 1A 2 . CONDUCTOR In some materials, the outer electrons of each atom or molecule are only weakly bound to it. These electrons are almost free to move throughout the body of the material and are called free electrons. They are also known as conduction electrons. When such a material is placed in an electric field, the free electrons drift in a direction opposite to the field. Such materials are called conductors. 3 . INSULATOR Another class o
Read more