Advertisements
Advertisements
Question
A magnetic needle is suspended freely so that it can rotate freely in the magnetic meridian. In order to keep it horizontal position, a weight of 0.2 g is kept on one end of the needle. If the pole strength of the needle is 20 Am, find the value of the vertical component of the Earth's magnetic field. (g = 9.8 ms-2)
Advertisements
Solution
Given: Here mass m = 0 .2 g = 0 .2 x 10-3 kg, g = 9.8 ms-2 Pole strength = 20 Am
To find: B =Earth's magnetic field=?
Now, Let mg = pole strength x B
∴ `0.2 xx 10^-3 xx 9.8 = 20 xx B`
∴ `(0.2 xx 10^-3 xx 9.8) /20`
B = 9 .8 x 10-5 T
APPEARS IN
RELATED QUESTIONS
The work done for rotating a magnet with magnetic dipole moment m, through 90° from its magnetic meridian is n times the work done to rotate it through 60°. Find the value of n.
A short bar magnet is placed in an external magnetic field of 700 gauss. When its axis makes an angle of 30° with the external magnetic field, it experiences a torque of 0.014 Nm. Find the magnetic moment of the magnet, and the work done in moving it from its most stable to the most unstable position.
Show that the orbital magnetic dipole moment of a revolving electron is `("evr")/2`
If the angle of dip at places A and Bare 30° and 45° respectively, then the ratio of horizontal component of earth's magnetic field at A to that at B will be
`[sin 45^circ = cos 45^circ = 1/sqrt2, sin pi/6 = 1/2, cos pi/6 = sqrt3/2]`
The force acting on a particle of charge q moving in a uniform magnetic field with velocity 'v' is ______
A charge 'q' is circulating with constant speed 'V' in a semi-circular loop of wire of radius 'R'. The magnetic moment of this loop is ______.
A bar magnet of magnetic moment 5 Am2 is placed in a uniform magnetic induction 3 x 10-5 T. If each pole of a magnet experiences a force of 2.5 x 10-4 N then the magnetic length of the magnet is ____________.
A charge 'q' is moving in a circular path of radius 'r' with uniform speed 'v'. The magnetic moment associated with the charged particle is ____________.
The magnetic moment (morb) of a revolving electron around the nucleus varies with the principal quantum number (n) as ______.
A current carrying closed loop in the form of a right angled isosceles ΔABC is placed in a uniform magnetic field acting along AB. If the magnetic force on the arm BC is F, then force on the arm AC is ______.
The magnetic moment of the current carrying loop shown in the figure is equal to ______.
State the formula for magnetic potential energy.
A magnetic needle is kept in a non-uniform magnetic field. It experiences ______.
