Magnetism and Matter Questions and Answers

4 42 A magnetic needle vibrates in the vertical plane perpendicular to the magnetic meridian Its time period is 2 seconds if the same needle vibrates in the horizontal plane and the time period is again 2 seconds what is the angle of dip at that place A 30 C 60 B 45 D None of the above

The primary origin of magnetism lies in 1 atomic current and intrinsic spin of electrons 2 polar and non polar nature of molecules 3 pauli exclusion principle

A circular loop of mass m and radius r lies on a table in x y plane as shown in figure A uniform magnetic field B is switched on along positive x axis The current in the loop so that loop just lift from table is B mg 2rB mg TUB mg ar B mg 4 TUB

A Column I with Colum shown in figure Match side a is placed on a frictionless horizontal surface A vertical force F is applied to edge as 200 A B Column I Mg Mg p Cube will move up F 4 2 F Mg 2 C F Mg Mg 4 D F q Column II r Cube will not exhibit motion Cube will begin to rotate and slip at A Normal reaction s a A p B q C s D r b A r B s C q D p c Aq B r C p D s d A s B p C r D q effectively at a 3 from A no motion 7 9 Moment of Inertia 47 Analogue of mass in rotational motion is a moment of inertia b torque c radius of gyration d angular momentu 48 The moment of inertia of a body depends upon

15 A magnet of length 2L and moment M is axially cut into two equal halves P and Q The piece P is bent in the form of semi circle and Q is attached to it as shown Its moment is N a C MI T M 2 P b d S N M 2 MT Q S

dgnet is broken into two equal pieces 23 Assertion For shown situation a small body A can be levitated in mid air if it is made of paramagnetic material A S be reduced to half Reason In non uniform external magnetic field paramagnetic material is attracted to regions of greater magnetic field

4 55 The two infinite plates shown in cross section in figure 4 268 carry amperes of current out of the page per unit width of plate Find the magnetic field at points P and Q P Q Figure 4 268

4 61 A vibration magnetometer consists of two identical bar magnets placed one over the other such that they are mutually perpendicular and bisect each other The time period of oscillation in a horizontal magnetic field is 4s If one of the magnets is taken away find the period of oscillation of the other in the same field from magr magnets Ans M 4 67 A resistivi consist and ne

agnet producing Find the couple apere is passed Ets plane o identical bar are mutually e period of 4 66 A magnet is suspended in the magnetic meridian with a untwisted wire The upper end of the wire is rotated through 180 to deflect the magnet by 30 from magnetic meridian Now this magnet is replaced by another magnet Now the upper end of the wire is rotated through 270 to deflect the magnet 30 from magnetic meridian Compare the magnetic moments of magnets Ans M M 5 8

a bar magnet of pole strength m and magnetic moment M is cut equally 4 times parallel t ts axis and 3 times perpendicular to its axis then the pole strength and magnetic moment o each piece are respectively m M 11 21 m M 21 m M 11 m M

The parameter of an equivalent circuit of a three phase induction motor affected by reducing the rms value of the supply voltage at the rated frequency is 1 rotor resistance

3 Two magnets A and B are identical and these are arranged as shown in the figure Their length is negligible in comparison to the separation between them A magnetic needle is placed between the magnets at point P which gets deflected through ar angle under the influence of magnets The ratio of distances d1 and d will be A d A 2 tan 0 1 3 B 2 tan 0 3 C 2 cot 0 1 3 D 2 cot 0 3 B

The angle of dip at a certain place on the earth is 45 The apparent angle of dip measured by a dip circle when its plane is at an angle 37 with the magnetic meridian is 45 tan 3 tan 1 1 Im 3 tan 1 5

A ferromagnetic material is placed in an external magnetic field The magnetic domains A increase in size B decrease in size C may increase or decrease in size D have no relation with the field Your Answer A Answer C

The horizontal component of the earth s magnetic field at a place is 3 1047 and the dip is tan 4 3 A metal rod of length 0 25m placed in the north south position is moved at a constant speed of 10 cm s towards the east The e m finduced in the rod will be lt silonely 1 zero 2 1 mV 3 5 mV 4 10mV

Maik Which of the following is not a vector quantity Magnetic field Magnetic susceptibility Intensity of magnetisation Magnetising field intensity hr n