Advertisements
Advertisements
प्रश्न
A short magnet produces a deflection of 37° in a deflection magnetometer in Tan-A position when placed at a separation of 10 cm from the needle. Find the ratio of the magnetic moment of the magnet to the earth's horizontal magnetic field.
Advertisements
उत्तर
Given :
Deflection in the magnetometer in the given position when placed in the magnetic field of a short magnet, θ = 37°
Separation between the magnet and the needle, d = 10 cm = 0.1 m
Let M be the magnetic moment of the magnet and `B_H` be Earth's horizontal magnetic field.
According to the magnetometer theory,
`M/B_H = (4pi)/u_0 (d^2 - l^2)^2/(2d) tan θ`
For the short magnet ,
`M/B_H = (4pi)/u_0 xx d^4/(2d) tan θ`
⇒`M/B_H = (4pi)/(4pi xx 10^-7) xx (0.1)^3/2 xx tan 37^circ`
⇒`M/B_H = 0.5 xx 0.75 xx 1 xx 10^4`
⇒`M/B_H = 3.75 xx 10^3 "A-m"^2"/"T`
APPEARS IN
संबंधित प्रश्न
State any two advantages of electromagnets over permanent magnets.
State two advantages of an electromagnet over a permanent magnet.
What are permanent magnets? Give one example ?
The force on a north pole, `vecF = mvecB` , parallel to the field `vecB` . Does it contradict our earlier knowledge that a magnetic field can exert forces only perpendicular to itself?
If the current is doubled, the deflection is also doubled in
The magnetic field at a point, 10 cm away from a magnetic dipole, is found to be `2.0 xx 10^-4 "T"` . Find the magnetic moment of the dipole if the point is (a) in end-on position of the dipole and (b) in broadside-on position of the dipole.
A bar magnet has a length of 8 cm. The magnetic field at a point at a distance 3 cm from the centre in the broadside-on position is found to be `4 xx 10^-6 "T"`.Find the pole strength of the magnet.
The coercive force for a certain permanent magnet is 4.0 × 104 A m−1. This magnet is placed inside a long solenoid of 40 turns/cm and a current is passed in the solenoid to demagnetise it completely. Find the current.
If the earth's magnetic field has a magnitude 3.4 × 10−5 T at the magnetic equator of the earth, what would be its value at the earth's geomagnetic poles?
A moving-coil galvanometer has a 50-turn coil of size 2 cm × 2 cm. It is suspended between the magnetic poles producing a magnetic field of 0.5 T. Find the torque on the coil due to the magnetic field when a current of 20 mA passes through it.
A deflection magnetometer is placed with its arms in north-south direction. How and where should a short magnet having M/BH = 40 A m2 T−1 be placed so that the needle can stay in any position?
A bar magnet takes π/10 second the complete one oscillation in an oscillation magnetometer. The moment of inertia of the magnet about the axis of rotation is 1.2 × 10−4 kg m2 and the earth's horizontal magnetic field is 30 μT. Find the magnetic moment of the magnet.
Soft iron is used to make the core of the transformer because of its ______.
What should be retentivity and coercivity of permanent magnet?
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from ______.
In a permanent magnet at room temperature ______.
A steel wire of length 1 has a magnetic moment m it is then bent into a semicircular arc. The new magnetic moment is
