**JEE Physic Paper set 3**

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S is the surface of a lump of magnetic material.

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The primary origin(s) of magnetism lies in

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A long solenoid has 1000 turns per metre and carries a current of 1 A. It has a soft iron core of μ_{r} = 1000. The core is heated beyond the Curie temperature, T_{c} .

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. Essential difference between electrostatic shielding by a conducting shell and magne-tostatic shielding is due to

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Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator

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A 25 cm long solenoid has radius 2 cm and 500 total number of turns. It carries a current of 15 A. If it is equivalent to a magnet of the same size and magnetisation M¯, then |M| is

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Three needles N_{1} N_{2} and N_{3} are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet, when brought close to them, will

(?) attract N_{1} strongly, but repel N_{2} and N_{3} weakly.

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The best material for the ore of a transformer is

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Electromagnetic waves travelling in a medium having relative permeability μ_{r} = 1.3 and relative permittivity E_{r} = 2.14. The speed of electromagnetic waves in medium must be

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1.8 × 10² ms^{-1}The condition under which a microwave over heats up a food item containing water molecules most efficiently is

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The correct option, if speeds of gamma rays, X-rays and microwave are V_{g}, V_{x} and V_{m} respectively will be.

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Waves in decreasing order of their wavelength are

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The electric field associated with an e.m wave in vacuum is given by E? =40 cos (kz – 6 × 10^{8}) i? , where E, Z and t are in volt/m, metre and seconds respectively. The value of wave vector K is

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The oscillating magnetic field in a plane electromagnetic wave is given as B_{y} = (8 × 10^{-6}) sin [2 × 10^{11}t+ 300πx] T, wavelength of the em wave is

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charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of electromagnetic waves produced by the oscillator is

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Light with an energy flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm2, the total momentum delivered (for complete absorption) during 30 minutes is

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Light with an energy flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm2, the total momentum delivered (for complete absorption) during 30 minutes is

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An electromagnetic wave travelling along z-axis is given as-E=E0 cos (kz – cot). Choose the incorrect option from the following;

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A charged particle oscillates about its mean equilibrium position with a frequency of 10^{9} Hz. For producing electromagnetic waves which one is not true?