Advertisements
Advertisements
प्रश्न
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
Advertisements
उत्तर
(b) 4.5 mV
e = vlb
`= 54 xx 5/18 xx 1 xx 3 xx 10^(-4)`
`= 45 xx 10^(-4) = 4.5 mV`
APPEARS IN
संबंधित प्रश्न
Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.
Give any ‘two’ points of differences between diamagnetic and ferromagnetic substances.
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?
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.
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.
The magnetic susceptibility of platinum is 0.0001. It's relative permeability is:
Which of the following statements is correct for diamagnetic materials?
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 ______.
What happens to a ferromagnetic material when its temperature increases above curie temperature?
Answer in brief.
Discuss the Curie law for paramagnetic material.
The susceptibility of a paramagnetic material is χ at 27° C. At what temperature its susceptibility be χ/3?
For a paramagnetic substance, the magnetic susceptibility is ______.
The susceptibility of a magnetic material is positive and small. The material is ______.
All atoms of a magnetic substance have a resultant magnetic moment even in absence of external magnetic field. The substance is ______.
Magnetization of the sample is ______.
If a magnetic field is applied to a liquid in one arm of a narrow U-tube, the liquid level in that arm is lowered. The liquid in U-tube arm is ______.
There are three needles 'N1', 'N2' and 'N3' made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. When a magnet is brought close to them, then it will ____________.
The product of magnetic susceptibility (`chi`) and absolute temperature (T) is constant for a ____________.
Above the curie temperature the susceptibility of ferromagnetic substance varies ____________.
A sphere of gold when brought towards a powerful magnet experiences ____________.
Which graph shows the variation of magnetic susceptibility (`chi`) with magnetizing field (H) for a paramagnetic substance?
Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
Why is diamagnetism, in contrast, almost independent of temperature?
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?
A certain region of space is to be shielded from magnetic fields. Suggest a method.
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond curie temperature, then it will show ______.
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 103 Am–1. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is ______.
The magnetic susceptibility is negative for ______.
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 ______.
The magnetic susceptibility for diamagnetic materials is ______.
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 ______.
S is the surface of a lump of magnetic material.
- Lines of B are necessarily continuous across S.
- Some lines of B must be discontinuous across S.
- Lines of H are necessarily continuous across S.
- Lines of H cannot all be continuous across S.
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.
If the magnetizing field on a ferromagnetic material is increased, its permeability ______.
Magnetic susceptibility for a paramagnetic and diamagnetic materials is respectively ______.
- Assertion (A): Diamagnetic substances exhibit magnetism.
- Reason (R): Diamagnetic materials do not have a permanent magnetic dipole moment.
Which of the following cannot modify an external magnetic field as shown in the figure?
The relative magnetic permeability of a substance X is slightly less than unity and that of substance Y is slightly more than unity, then ______.
Explain the Domain theory in brief.
Explain the meaning of the following statement:
Curie temperature for soft iron is 770°C.
Magnetic susceptibility of a diamagnetic substance ______.
