The magnetic field produced by current I1 at any point on wire RS is B1 This field acts perpendicular to the wire RS and points into the plane of paper. It exerts a force on current carrying wire RS. The force acting on length of the wire RS will be l 90 lB1sin 2 2 I I2 l. I1 I1I l Force per unit length, 2 F2 I1 I f l 10. A circular coil of turns and diameter a current It is unwound and rewound to make ‘N’ ‘d’ carries ‘I’. another coil of diameter current the same. Calculate the ratio of the magnetic ‘2d’, ‘I’ remaining moments of the new coil and the original coil. Ans: Magnetic moment (m) = NIA Length of wire remains same, so = Thus NB NA/2 2/1 mA/mB= Which one of the two, an ammeter or a milliammeter, has a higher resistance and why? Ans: As the shunt resistance is connected in parallel with the galvanometer, so the milliammeter will have a higher resistance than the ammeter. A circular coil of N turns and radius R carries a current I. It is unwound and rewound to make another coil of radius R/2, current I remaining same. Calculate the ratio of the magnetic moments of the now coil and the original coil. Ans: M1= NIA= NIπR2 M2=2 πNI (R/2)2 M2/M1 = ½ 13. The following figure shows the variation of intensity of magnetization I versus the applied magnetic field intensity H for two magnetic materials A and B. Identify the materials A and B Draw the variation of susceptibility with temperature for B.
The magnetic field produced by current I1 at any point on wire RS is This field acts perpendicular to the wire RS and points into the plane of paper. It exerts a force on current carrying wire RS. The force acting on length l of the wire RS will be I 2 lB1sin I2 l. I1 I1I 2 l Force per unit length, f F2 I1 I 2 l 10. A circular coil of ‘N’ turns and diameter ‘d’ carries a current ‘I’. It is unwound and rewound to make another coil of diameter ‘2d’, current ‘I’ remaining the same. Calculate the ratio of the magnetic moments of the new coil and the original coil. Ans: Magnetic moment (m) = NIA Length of wire remains same, so NB = NA/2 Thus mA/mB= 2/1 Which one of the two, an ammeter or a milliammeter, has a higher resistance and why? Ans: As the shunt resistance is connected in parallel with the galvanometer, so the milliammeter will have a higher resistance than the ammeter. A circular coil of N turns and radius R carries a current I. It is unwound and rewound to make another coil of radius R/2, current I remaining same. Calculate the ratio of the magnetic moments of the now coil and the original coil. Ans: M1= NIA= NIπR2 M2=2 πNI (R/2)2 M2/M1 = ½ 13. The following figure shows the variation of intensity of magnetization I versus the applied magnetic field intensity H for two magnetic materials A and B. Identify the materials A and B Draw the variation of susceptibility with temperature for B. 90 B1