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JEE PHYSICS MCQ: MAGNETIC EFFECT OF CURRENT
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A circular coil carrying a certain current produces a magnetic field at its centre. The coil is now rewound so as to have 4 turns and the same current is passed through it. The new magnetic field at the centre is
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Correct option: B
Option A () is correct because it is the amplitude of the electric field of radiation at the given distance from the lamp, calculated using the Poynting vector and the relationship between electric and magnetic fields.
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A needle made of bismuth is suspended freely in a magnetic field. The angle which the needle makes with the magnetic field is:
Assertion: If a charged particles is moving in perpendicular uniform magnetic field, its kinetic energy does not change
Reason: Velocity of charge particle is not changing in magnetic field. Pick out the wrong statement : A steady current is flowing in a circular coil of radius , made up of a thin conducting wire. The magnetic field at the center of the loop is . Now, a circular loop of radius is made from the same wire without changing its length, by unfolding and refolding the loop, and the same current is passed through it. If new magnetic field at the center of the coil is , then the ratio is Lorentz force can be calculated by using the formula Two particles and having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular path of radius and respectively. The ratio of mass of to that of is :
Reason: Velocity of charge particle is not changing in magnetic field. Pick out the wrong statement : A steady current is flowing in a circular coil of radius , made up of a thin conducting wire. The magnetic field at the center of the loop is . Now, a circular loop of radius is made from the same wire without changing its length, by unfolding and refolding the loop, and the same current is passed through it. If new magnetic field at the center of the coil is , then the ratio is Lorentz force can be calculated by using the formula Two particles and having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular path of radius and respectively. The ratio of mass of to that of is :