Identify the correctly matched pair
Diamagnetic — Gadolinium
Soft ferromagnetic — Alnico
Hard ferromagnetic — Copper
Paramagnetic — Sodium
D.
Paramagnetic — Sodium
Some substances when placed in a magnetic field, are feebly magnetised in the direction of the magnetising field. These substances, when brought close to a pole of a powerful magnet, are attracted towards the magnet. These are called 'paramagnetic' substances and their magnetism is called 'paramagnetism'.
For examples of paramagnetic substances are aluminium, sodium, platinum, copper, manganese, antimony, chloride, liquid oxygen. Solution of salts of iron and nickel, etc
So, correctly matched pair are paramagnetic — Sodium.
If the radius of the dees of cyclotron is r, then the kinetic energy of a proton of mass m accelerated by the cyclotron at an oscillating frequency v is
If a magnetic dipole of moment M situated in the direction of a magnetic field B is rotated by 180°, then the amount of work done is
MB
2 MB
Zero
The polarity of induced emf is given by
Ampere's circuital law
Biot-Savart's law
Lenz's law
Fleming's right hand rule
In an L-C-R series circuit, at resonance
the current and voltage are in phase
the impedance is maximum
the current is minimum
the quality factor is independent of R
A conducting ring of radius 1 m kept in a uniform magnetic field B of 0.01 T, rotates uniformly with an angular velocity 100 rads-1 with its axis of rotation perpendicular to B. The maximum induced emf in it is
A step-down transformer increases the input current 4 A to 24 A at the secondary. If the number of turns in the primary coil is 330, the number of turns in the secondary coil is
60
50
55
45
In a plane electromagnetic wave, the electric field of amplitude 1 Vm-1 varies with time in free space. The average energy density of magnetic field is (in Jm-2)
8.86 × 10-12
4.43 × 10-12
17.72 × 10-12
2.21 × 10-12
Which one of the following is the property of a monochromatic, plane electromagnetic wave in free space?
Electric and magnetic fields have a phase difference of
The energy contribution of both electric and magnetic fields are equal.
The direction of propagation is in the direction of electric field E
The pressure exerted by the wave is the product of energy density and the speed of the wave
A plane square sheet of charge of side 0.5 m has uniform surface charge density. An electron at 1 cm from the centre of the sheet experiences a force of 1.6 x 10-12 N directed away from the sheet. The total charge on the plane square sheet is (ε0 = 8.854 × 10-12 C2 m-2 N-1)
16.25 µC
− 22.15 µC
− 44.27 µC
144.27 µC