Chapter-5 Questions class 12 physics

 Magnetisms and matter 

Q.1 If the horizontal component of earth’s magnetic field at a place where the angle of dip is 60° is 0.4×10^ -4 T, calculate the vertical component and the resultant magnetic field at that place.           Ans.  BE = 8 x 10^-5 T and Bv= 4 root3 x 10^-5T 

Q.2 The declaration at a place is 15° west of north. In which direction should a ship be steered with respect to compass needle so that it reaches a place due east.          Ans 105°

Q.3 A ship is to reach a place 10° south of West. In which direction should it be steered with respect to compass needle if the declaration at a place is 18° West of North.      82°

Q.4 A ship is sailing due east according to mariners compass. If the declaration of that place is 18° East of North, what is the true direction of the ship?              18° South of East

Q.5 Sketch the magnetic field lines due to a bar magnet when it is placed with its north pole towards north pole of the earth

Q.6 The dipole moment of each molecule of a paramagnetic gas is 1.5×10^-23 Am^2. The temperature of gas is 27°C and the number of molecules per unit volume in it is 2×10^26 /m^3. The maximum possible intensity of magnetisation in the case will be?              3 x 10^3 A/m 

Q.7 The magnetic induction and magnetising field in a sample of magnetic material are 1 Weber/ m^2 and 2×10^3 A per metre respectively. Find a) magnetic permeability b) relative permeability of the material, c) magnetic susceptibility d) intensity of magnetisation.                   Ans . a) 0.5 x 10^-3.   b) 397  c) 396 d) 8 x 10^5

Q.8 A solenoid of 500 turns per metre is carrying a current of 3A. Its core is made of iron which has a relative permeability of 5000. Determine the magnitude of the magnetic intensity, magnetisation and the magnetic field inside the core.               Ans. 1500A/m , appx. 7.5 x 10^6 A/m , 9.426 

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