Page 1 CBSE TEST PAPER-03 CLASS - XII PHYSICS (Magnetic effects of current and magnetism) [ANSWERS] Ans 1. Intensity of magnetization increases with the increase in applied magnetic field. Ans 2. Curie temperature of iron is about 770 0 C but when it is heated to a very higher temperature magnetism of iron further gets lost and it will not retain magnetism. Ans 3. Magnetic field due to semicircle QR at C. is 1 1 1 0 2 = 2 I B R µ p µp Magnetic field due to semicircle is at C is 2 2 1 0 2 = 2 I B R µ p µp Net field B = B 1 – B 2 1 2 1 2 1 0 1 1 = 2 I - 2 4 0 1 1 = - 4 B R R I B R R µ p p µ ? ? ? ? ? ? ? ? ? ? ? ? Ans 4. m = NIA m = 1× 10 -4 × 2 m = 2 × 10 -4 Am 2 . Ans 5. (a) B = 0.10T ? = 0 0 (Normal to plane of the coil) I = 5.0 A , Area = 10 -5 m2 n = 10 29 m -3 0 sin sin 0 0 MB MB t ? t = = = (b) Total force on the coil = 0 Newton (c) Fav = q (vd B × ) ( I = neAVd) Fav = qI B neA × Fav = 29 5 5 0.10 10 10 IB nA - × = × 25 5 10 Fav N - = × Page 2 CBSE TEST PAPER-03 CLASS - XII PHYSICS (Magnetic effects of current and magnetism) [ANSWERS] Ans 1. Intensity of magnetization increases with the increase in applied magnetic field. Ans 2. Curie temperature of iron is about 770 0 C but when it is heated to a very higher temperature magnetism of iron further gets lost and it will not retain magnetism. Ans 3. Magnetic field due to semicircle QR at C. is 1 1 1 0 2 = 2 I B R µ p µp Magnetic field due to semicircle is at C is 2 2 1 0 2 = 2 I B R µ p µp Net field B = B 1 – B 2 1 2 1 2 1 0 1 1 = 2 I - 2 4 0 1 1 = - 4 B R R I B R R µ p p µ ? ? ? ? ? ? ? ? ? ? ? ? Ans 4. m = NIA m = 1× 10 -4 × 2 m = 2 × 10 -4 Am 2 . Ans 5. (a) B = 0.10T ? = 0 0 (Normal to plane of the coil) I = 5.0 A , Area = 10 -5 m2 n = 10 29 m -3 0 sin sin 0 0 MB MB t ? t = = = (b) Total force on the coil = 0 Newton (c) Fav = q (vd B × ) ( I = neAVd) Fav = qI B neA × Fav = 29 5 5 0.10 10 10 IB nA - × = × 25 5 10 Fav N - = × Ans 6. A particle of mass (m) and change (q) moving with velocity? normal to B describes a circular path if 2 0 2 qBvsin ( =90 ) => qvB => (1) mv r mv r mv r Bq ? ? = ? = = - - - - Since Time period of Revolution During circular path = Circumference of circle velocity => 2 r T v p = ( .(1) Bqr v from eg m ? = ) => T = 2 r m Bqr p × 2 -----(2) m T Bq p = Kinetic energy K.E = 2 1 mv 2 => KE = 2 1 2 Bqr m m ? ? ? ? ? ? 2 2 2 (3) 2 B q r KE m = - - - Ans 7. If n be the no, of turns per unit length I be the current flowing through the Toroid Then from Ampere’s circuital law Page 3 CBSE TEST PAPER-03 CLASS - XII PHYSICS (Magnetic effects of current and magnetism) [ANSWERS] Ans 1. Intensity of magnetization increases with the increase in applied magnetic field. Ans 2. Curie temperature of iron is about 770 0 C but when it is heated to a very higher temperature magnetism of iron further gets lost and it will not retain magnetism. Ans 3. Magnetic field due to semicircle QR at C. is 1 1 1 0 2 = 2 I B R µ p µp Magnetic field due to semicircle is at C is 2 2 1 0 2 = 2 I B R µ p µp Net field B = B 1 – B 2 1 2 1 2 1 0 1 1 = 2 I - 2 4 0 1 1 = - 4 B R R I B R R µ p p µ ? ? ? ? ? ? ? ? ? ? ? ? Ans 4. m = NIA m = 1× 10 -4 × 2 m = 2 × 10 -4 Am 2 . Ans 5. (a) B = 0.10T ? = 0 0 (Normal to plane of the coil) I = 5.0 A , Area = 10 -5 m2 n = 10 29 m -3 0 sin sin 0 0 MB MB t ? t = = = (b) Total force on the coil = 0 Newton (c) Fav = q (vd B × ) ( I = neAVd) Fav = qI B neA × Fav = 29 5 5 0.10 10 10 IB nA - × = × 25 5 10 Fav N - = × Ans 6. A particle of mass (m) and change (q) moving with velocity? normal to B describes a circular path if 2 0 2 qBvsin ( =90 ) => qvB => (1) mv r mv r mv r Bq ? ? = ? = = - - - - Since Time period of Revolution During circular path = Circumference of circle velocity => 2 r T v p = ( .(1) Bqr v from eg m ? = ) => T = 2 r m Bqr p × 2 -----(2) m T Bq p = Kinetic energy K.E = 2 1 mv 2 => KE = 2 1 2 Bqr m m ? ? ? ? ? ? 2 2 2 (3) 2 B q r KE m = - - - Ans 7. If n be the no, of turns per unit length I be the current flowing through the Toroid Then from Ampere’s circuital law ( ) ( ) ( ) ( ) 0 0 2 0 0 0 2 0 0 0 . d = total current flowing in the toroid . d = 2 cos 0 = 2 = 2 . 2 r = 2 B = r r B B rnI Bd rnI B d rnI B rnI onI p p µ µ p µ p µ p p µ p µ × ? ? ? ? l l l l Ans 8. Force experienced by the charged particle moving at right angles to uniform magnetic field B with velocity v is given by F = q ( v B × ) Initially Dee D 1 is negatively charged and Dee D 2 is positively charged so, the positive ion will get accelerated towards Dee D 1 since the magnetic field is uniform and acting at right angles to the plane of the Dees so the ion completes a circular path in D1 when ions comes out into the gap, polarity of the Dee’s gets reversed used the ion is further accelerated towards Dee D 2 with greater speed and cover a bigger semicircular path. This process is separated time and again and the speed of the ion becomes faster till it reaches the periphery of the dees where it is brought out by means of a deflecting plate and is made to bombard the target. Since F = qVBsin90 0 provides the necessary centripetal force to the ion to cover a circular path so we can say 2 mv qvB r = => r = ----- (1) mv Bq Time period = 2 2 2 = = r rm m v Bqr Bq p p p V = 1 => frequency is independent of velocity 2 Bq T m p =Read More

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