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प्रश्न
State applications of eddy currents.
Write two applications of eddy current.
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उत्तर
- Dead-beat galvanometer: The coil is wound on a light aluminium frame in a pivoting moving-coil galvanometer for measuring current. The coil is swiftly brought to rest by the rotation of the metal frame in the magnetic field, which causes eddy currents in the frame that oppose the rotation. This causes the galvanometer to stop working.
- Electric brakes: When a conducting plate is pushed into or pulled out of a magnetic field fast, the interaction between the moving conductor’s eddy currents and the field slows down the velocity. This property of eddy currents is used in vehicles as a method of braking.
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संबंधित प्रश्न
Two spherical bobs, one metallic and the other of glass, of the same size are allowed to fall freely from the same height above the ground. Which of the two would reach earlier and why?
Give one example of use of eddy currents.
Describe briefly three main useful application of eddy currents ?
If the magnetic field outside a copper box is suddenly changed, what happens to the magnetic field inside the box? Such low-resistivity metals are used to form enclosures which shield objects inside them against varying magnetic fields.
A metallic bob A oscillates through the space between the poles of an electromagnet (See the figure). The oscillations are more quickly damped when the circuit is on, as compared to the case when the circuit is off. Explain.
A metal sheet is placed in front of a strong magnetic pole. A force is needed to ______________ .
(a) hold the sheet there if the metal is magnetic
(b) hold the sheet there if the metal is nonmagnetic
(c) move the sheet away from the pole with uniform velocity if the metal is magnetic
(d) move the sheet away from the pole with uniform velocity if the metal is nonmagnetic.
Neglect any effect of paramagnetism, diamagnetism and gravity.
How are eddy currents generated in a conductor which is subjected to a magnetic field?
In which of the following devices, the eddy current is not used ______
Why and where are eddy currents are undesirable? How are they minimized?
Give the uses of Foucault current.
A constant retarding force of50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms-1. How long does the body take to stop?
If the length of a simple pendulum increases by 5%, then its period shall increase by ______.
Which one is not an application of eddy current?
Eddy currents are also known as ______
A metal plate is getting heated. It can be because ______.
- a direct current is passing through the plate.
- it is placed in a time varying magnetic field.
- it is placed in a space varying magnetic field, but does not vary with time.
- a current (either direct or alternating) is passing through the plate.
