Ans: 1) A is paramagnetic material. 2) B is diamagnetic material. THREE MARKS QUESTIONS 1. State law for magnetic field produced at a point due to a small current element. How will you find the direction of magnetic field? Ans. Consider a current element of a conductor carrying current I. let P be a point having dl . Let and position vector with respect to current element be the angle between r dl dl r According to Biot-Savart law, the magnetic field dB at point P due to current element is 1 (i) (ii) (iii) (iv) dB I dB dl dB sin dB r 2 Combining all the four factors, we get I dl dB 2 r sin I dl dB = K 2 r The proportionality constant K depends on the medium between point P and the current element and the system of units chosen. For free space and in SI units, 0 7 T 10 K I dl sin dB 4 2 r As the direction of is perpendicular to the plane of and , so from the above dB dl r
Ans: 1) A is paramagnetic material. 2) B is diamagnetic material. THREE MARKS QUESTIONS 1. State law for magnetic field produced at a point due to a small current element. How will you find the direction of magnetic field? Ans. Consider a current element dl of a conductor carrying current I. let P be a point having . Let and position vector r with respect to current element dl be the angle between dl r According to Biot-Savart law, the magnetic field dB at point P due to current element is (i) dB I (ii) dB dl (iii) dB sin (iv) dB 1 r 2 Combining all the four factors, we get dB I dl r 2 dB = K I dl r 2 The proportionality constant K depends on the medium between point P and the current element and the system of units chosen. For free space and in SI units, K 0 10 T dB I dl r 2 and , so from the above As the direction of dB is perpendicular to the plane of dl r sin sin 4 7
physics-xii-15-16.docx