MtG Objective NCERT P THE EARTH S MAGNETISM 41 The earth
Last updated: 6/10/2023
MtG Objective NCERT P THE EARTH S MAGNETISM 41 The earth behaves as a magnet with magnetic fi pointing approximately from the geographic a North to South c East to West b South to North d West to East 42 The strength of the earth s magnetic field is a constant everywhere zero everywhere b c having very high value d vary from place to place on the earths surface 43 Which of the following is responsible for the earth magnetic field a Convective currents in earth s core b Diversive current in earth s core c Rotational motion of earth d Translational motion of earth 44 Which of the following independent quantities is not used to specify the earth s magnetic field a Magnetic declination 0 b Magnetic dip 8 c Horizontal component of earth s field B d Vertical component of earth s field B 5 If you made a map of magnetic field lines at Melbourne in Australia then the magnetic field lines seem to be a go into the ground b come out of the ground c maintain a spiral path on the surface of earth d move on helical path above the surface of ground 6 The horizontal and vertical components of earth s magnetic field at a place are 0 3 G and 0 52 G The earth s magnetic field and the angle of dip are a 0 3 G and 8 30 c 0 5 G and 8 50 b 0 4 G and 8 40 d 0 6 G and 8 60 7 Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth The angle of dip at a point on the geographical equator is a always zero b positive negative or zero c unbounded d always negative Consider the plane S formed by the dipole axis and the axis of earth If P be the point of intersection of the geographical and magnetic equators then the declination and dip angle at point Pare Magnetism and Matter a 0 11 3 c 11 3 11 3 b 11 3 0 d 0 0 19 The dip angle at a location in southern India is about 18 Then the dip angle in Britain will be b lesser than 18 d zero a greater than 18 c equal to 18 50 The angle of dip at a certain place where th horizontal and vertical components of the earth magnetic field are equal is b 75 a 30 d 45 51 The vertical component of earth s magnetic field a place is 3 times the horizontal component t value of angle of dip at this place is c 60 d 90 a 30 b 45 c 60 52 At a certain location in Africa compass points west of geographic north The north tip of magn needle of a dip circle placed in the plane of magn meridian points 60 above the horizontal horizontal component of earth s field is meas to be 0 16 G The magnitude of earth s field at location is a 0 32 G c 4 2 G b d 0 42 G 3 2 G 53 Assume the dipole model for earth s mag field B which is given by the vertical compone and the horiz Hom 41 Ho 2mcos8 magnetic field By 4x P component of magnetic field B where 0 90 latitude as measured from ma equator then the loci of point for which dipa 45 a tan 3 c tan 0 5 b tan 2 d tan 1 54 The angles of dip at the poles and the respectively are a 30 60 c 45 90 b 0 90 d 90 0 55 At a given place on earth s surface the h component of earths magnetic field is 2 and resultant magnetic field is 4 x 105 T of dip at this place is a 30 b 60 c 90 d 56 The earth s field departs from its dip substantially at large distance gre about 3000 Km The responsible facto distortion is