Home/Class 12/Physics/

Question and Answer

Two identical looking iron bars \(A\)  and \(B\)  are given, one of which is definitely known to be magnetised. \((\) We do not know which one. \()\) How would one ascertain whether or not both are magnetised? If only one is magnetised, how does one ascertain which one? \([\) Use nothing else but the bars \(A\)  and \(B.]\)

Answer

When there is a repulsive force between the two bars, then both are magnetised. If it is always attractive, then one of them is not magnetised. The strength of the magnetic field is the strongest at the two ends \((\) poles \()\) and weakest at the middle region. This fact may be used to find out  whether \(A\)  or \(B\)  is the magnet. To see which one of the two bars is a magnet, take first \((\) bar-A \()\)  and lower one of its ends; first on one of the ends of the other \((\) bar-B \()\) , and then on the middle of \(B\) . If you observe that in the middle of \(B\) , \(A\)  experiences no force, then \(B\)  is magnetised. If you do not find any change from the end to the middle of \(B\) , then \(A\)  is magnetised.
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
Correct27
Incorrect0
Watch More Related Solutions
What is the magnitude of the equatorial and axial fields due to a bar magnet of length \(5\;{cm}\) at a distance of \(50\;{cm}\) from its mid-point? The magnetic moment of the bar magnet is \(0.40\; A m^2\).
For one mole of a van der Waals' gas when \(b=0\) and \(T=300K\) , the \(pV\) vs \(1/V\) plot is shown below. The value of the van der Waals’ constant \(a \ (atm \ L\  mol^{-2})\)

( )
A. \(1.0\)
B. \(4.5\)
C. \(1.5\)
D. \(3.0\)
If the alignment of magnetic moments in a substance is in a compensatory way so as to give zero net magnetic moment, then the substance is said to be
(a) Ferromagnetism
(b) Anti-ferromagnetism
(c) Ferrimagnetism
(d) Diamagnetism.
The outer surface of a cylinder containing a gas is rubbed vigorously by a polishing machine. The cylinder and its gas become warm. Is the energy transferred to the gas heat or work?
Figure shows a small magnetised needle \(P\)  placed at a point \(O\) . The arrow shows the direction of its magnetic moment. The other arrows show different positions \((\) and orientations of the magnetic moment \()\) of another identical magnetised needle \(Q\) . In which configuration the system is not in equilibrium?
Which configuration corresponds to the lowest potential energy among all the configurations shown?

The number of \(Cl^-\)  ions present around each \(Na^{+}\)  ion in \(NaCl\) crystal lattice is
(a) \(3\)
(b) \(4\)
(c) \(8\)
(d) \(6\)
State whether the magnetic field lines shown are correct or wrong for the image shown. 

An ideal gas is taken from an initial state i to a final state f in such a way that the ratio of the pressure to the absolute temperature remains constant. What will be the work done by the gas?
According to molecular orbital theory\(,\) which of the following statements is(are) correct? ( )
A. \(C^{2-}_{2}\) is expected to be diamagnetic
B. \(O^{2+}_{2}\) is expected to have a longer bond length than \(O_{2}\)
C. \(N^{+}_{2}\) and \(N^{-}_{2}\) have the same bond order
D. \(He^{+}_{2}\) has the same energy as two isolated \(He\) atoms
State whether the magnetic field lines shown are right or wrong.

Load More