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JEE PHYSICS MCQ: MAGNETIC EFFECT OF CURRENT
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The coercivity of a bar magnet is . It is to be demagnetised by placing it inside a solenoid having number of turns per unit length . The current flowing through the solenoid is
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Correct option: C
Option C () is correct because it's the current required to demagnetize the magnet, calculated using the coercivity and number of turns per unit length.
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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 :