Advertisements
Advertisements
प्रश्न
Choose the correct option:
A rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely. Its period of oscillation is T′, the ratio of T′/T is ______.
पर्याय
`1/(2sqrt2)`
`1/2`
2
`1/4`
Advertisements
उत्तर
A rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely. Its period of oscillation is T′, the ratio of T′/T is `1/2`.
Explanation:
Calculate time period (T) of the complete magnet:
T = `2pi sqrt(I/(mu * B)`
Calculate moment of inertia (I) of the complete magnet:
`I = 1/12 ml^2` .....(1)
Calculate time period (T) of the broken magnet
T' = `2pi sqrt((I"'")/(mu"'" * B)` ......(2)
Calculate moment of inertia (I') of the broken magnet
`I = 1/12 * m/2 * (l/2)^2 = 1/12 (ml^2)/8`
From equation (1):
`I"'" = I/8` also `mu = mu/2`
Substitute moment of inertia (1) in (2):
T' = `2pi sqrt((I"'")/(mu"'" * B)) = 2pi sqrt(I/(8 * mu"'" * B)`
Calaculate ratio `T/T`:
`T/T = (2pisqrt(I/(8 * mu/2 * B)))/(2pi sqrt(I/(mu*B))`
`T/T = 1/2`.
APPEARS IN
संबंधित प्रश्न
Give any ‘two’ points of differences between diamagnetic and ferromagnetic substances.
An iron rod of the area of cross-section 0.1m2 is subjected to a magnetizing field of 1000 A/m. Calculate the magnetic permeability of the iron rod. [Magnetic susceptibility of iron = 59.9, magnetic permeability of vacuum = 4π x 10-7 S. I. unit]
Out of the two magnetic materials, 'A' has relative permeability slightly greater than unity while 'B' has less than unity. Identify the nature of the materials 'A' and 'B'. Will their susceptibilities be positive or negative?
Show diagrammatically the behaviour of magnetic field lines in the presence of (i) paramagnetic and (ii) diamagnetic substances. How does one explain this distinguishing feature?
A meter gauge train is heading north with speed 54 km/hr in earth's magnetic field 3 x 10-4T. The e.m.f. induced across the axle joining the wheels is ..........
(a) 0.45 mV
(b) 4.5 mV
(c) 45 mV
(d) 450 m V
The susceptibility of a magnetic material is 0·9853. Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.
Explain Curie’s law for a paramagnetic substance.
Which of the following substances are diamagnetic?
Bi, Al, Na, Cu, Ca and Ni
Which of the following substances are para-magnetic?
Bi, Al, Cu, Ca, Pb, Ni
The susceptibility of a magnetic material is − 2.6 × 10−5. Identify the type of magnetic material and state its two properties.
The relative magnetic permeability of a magnetic material is 800. Identify the nature of magnetic material and state its two properties.
A tangent galvanometer shows a deflection of 45° when 10 mA of current is passed through it. If the horizontal component of the earth's magnetic field is `B_H = 3.6 xx 10^-5 "T"` and radius of the coil is 10 cm, find the number of turns in the coil.
Answer the following question.
Write three points of differences between para-, dia- and ferromagnetic materials, giving one example for each.
Identify the following magnetic materials :
Choose the correct option:
A magnetising field of 360 Am−1 produces a magnetic flux density (B) = 0.6T in a ferromagnetic material. What is its permeability in Tm A−1?
A paramagnetic gas has 2.0 × 1026 atoms/m with atomic magnetic dipole moment of 1.5 × 10−23 A m2 each. The gas is at 27°C.
- Find the maximum magnetization intensity of this sample.
- If the gas in this problem is kept in a uniform magnetic field of 3 T, is it possible to achieve saturation magnetization? Why?
Two identical bar magnets each of magnetic moment M, separated by some distance are kept perpendicular to each other. The magnetic induction at a point at the same distance d from the centre of magnets, is (µ0 = permeability of free space)
For a paramagnetic substance, the magnetic susceptibility is ______.
The susceptibility of a magnetic material is positive and small. The material is ______.
Magnetic material can be easily magnetized if magnetic susceptibility is ______.
The magnetic property of magnetic substance is associated with ____________.
The product of magnetic susceptibility (`chi`) and absolute temperature (T) is constant for a ____________.
A sphere of gold when brought towards a powerful magnet experiences ____________.
A small quantity of paramagnetic liquid is taken in a watch - glass and kept on two dissimilar magnetic poles. The liquid ____________.
The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?
A short bar magnet has a magnetic moment of 0.48 J T−1. Give the direction and magnitude of the magnetic field produced by the magnet at a distance of 10 cm from the centre of the magnet on
- the axis,
- the equatorial lines (normal bisector) of the magnet.
If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?
Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?
A certain region of space is to be shielded from magnetic fields. Suggest a method.
The given figure represents a material which is ______.
Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called ______.
Two identical bar magnets are fixed with their centres at a distance d apart. A stationary charge Q is placed at P in between the gap of the two magnets at a distance D from the centre O as shown in the figure. The force on the charge Q is ______.
Earth's magnetic field analyses has a horizontal component except at:-
A hydrogen atom is paramagnetic. A hydrogen molecule is
Most of the substance show which of the magnetic property:-
The universal property of all substances is ______.
A paramagnetic sample shows a net magnetisation of 8 Am–1 when placed in an external magnetic field of 0.6 T at a temperature of 4 K. When the same sample is placed in an external magnetic field of 0.2 T at a temperature of 16 K, the magnetisation will be ______.
A long solenoid has 1000 turns per metre and carries a current of 1 A. It has a soft iron core of µr = 1000. The core is heated beyond the Curie temperature, Tc.
- The H field in the solenoid is (nearly) unchanged but the B field decreases drastically.
- The H and B fields in the solenoid are nearly unchanged.
- The magnetisation in the core reverses direction.
- The magnetisation in the core diminishes by a factor of about 108.
A permanent magnet in the shape of a thin cylinder of length 10 cm has M = 106 A/m. Calculate the magnetisation current IM.
Explain quantitatively the order of magnitude difference between the diamagnetic susceptibility of N2 (~5 × 10–9) (at STP) and Cu (~10–5).
From molecular view point, discuss the temperature dependence of susceptibility for diamagnetism, paramagnetism and ferromagnetism.
Magnetic susceptibility for a paramagnetic and diamagnetic materials is respectively ______.
Which of the following cannot modify an external magnetic field as shown in the figure?
Explain the origin of paramagnetism on the basis of atomic structure.
