Explain the following: The north end of a freely suspended magnetic needle gets attracted towards a piece of soft iron placed a little distance away from the needle.

The effect due to uniform magnetic field on a freely suspended magnetic needle is as follows

Explain the following: Several soft iron pins can cling, one below the other, from the pole of a magnet.

Centers of two similar coils P and Q having same number of turns are located at the coordinates (0.4,0) and (0,0.3) such that the plane of coils are perpendicular to X-and Y-axis respectively. The areas of cross section of coils P and Q are in the ration 4:3 Coil P has 16 A current in clockwise direction and coil Q has 9sqrt3A current in anticlockwise direction as seen from the origin. A small compass needle is placed at the origin. Find the deflection in the needle, assuming the earth's magnetic field negligible and the radii of the coils very small compared to their distances from the origin.

Dip circle can be used to determine the angle of dip at a place . Dip circle consists of a magnetic needle free to rotate in a vertical plane . The end points of the needle move over a vertical circular scale . This arrangement can rotate about vertical axis . The angle rotated about vertical axis can be read from a horizontal scale . If a dip circle is further rotated about vertical axis by 60^(@) then the apparent dip at that position will be

A magnetic needle free to rotate in a horizontal plane is placed at the centre of a circular current-carrying coil whose axis is perpendicular to the magnetic meridian at that place. It is also known that the magnetic declination at this place is zero and in this condition, the magnetic needle is pointing towards conditions, the magnetic needle is pointing towards the north-west. Now, if we reverse the direction of current in the coil, then the magnetic needle will

Answer the following: a) A circular loop of Radius R carries a current I . Obtain an expression for the magnetic field at a point on its axis at a distance of x from its centre. b) A conducting rod of length 2 m is placed on a horizontal table in north-south direction. It carries a current of 5 A from south to north. Find the direction and magnitude of magnetic force acting on the rod. Given that Earth's magnetic field at the place is 0.6 xx 10^(-4) T and angle of dip is (pi/6)

A metallic rod CD rests on a thick metallic wire PQRS with arms PQ and RS parallel to each other, at a distance l = 40 cm, as shown in following figure. A uniform magnetic field B = 0:1 T acts perpendicular to the plane of this paper, pointing inwards (i.e., away from the reader). The rod is now made to slide towards right, with a constant velocity of v=5.0ms^(-1) . (i) How much emf is induced between the two ends of the rod CD ? (ii) What is the direction in which the induced current flows ?

The needle of a deflection magnetometer deflects through 45^@ from north to south when the instrument is used in Tan-A position with a magnet of length 10cm placed at a distance of 25cm. (a) Find the magnetic moment of the magnet if the earth's horizontal magnetic field is 20 muT . (b) If the magnetometer is used in Tan-B position with the same magnet at the same separation from the needle, what will be the deflection?

A magnetic dipole of magnetic moment 6Am^(2) is lying in a horizontal plane with its north pole pointing toward 60^(@) East of North. Find the net horizontal magnetic field at a point· on the axis of the magnet 0.2m away from it. Horizontal Component of earth field at this place is 30 mu T .

A metal sphere is suspended from a nylon thread. Initially, the metal sphere is uncharged. When a positively charged glass rod is brought close to the metal sphere, the sphere is drawn towards the rod. But if the sphere touches the rod, it suddenly flies away from the rod. Explain, why the sphere is first attracted then repelled?