NEET Physics · Flashcards
This deck has 22 flashcards on Magnetic Effects of Current & Magnetism for NEET Physics, from NCERT Class 12. It covers the NCERT chapters Moving Charges and Magnetism and Magnetism and Matter.
Master the Magnetic Effects of Current and Magnetism for NEET: High-yield flashcards covering Biot-Savart, Ampere's Law, Galvanometer conversions, and Magnetic Properties of Materials.
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Card 1 of 22
State the Biot-Savart Law in vector form.
Hint: The direction of dB is perpendicular to the plane containing dl and r (Right-Hand Rule).
Answer
dB = (μ₀ / 4π) × [I(dl × r) / r³] Where dB is the magnetic field due to a current element Idl, and r is the position vector from the element to the point.
Card 2 of 22
What is the Magnetic Field (B) at the center of a circular current-carrying loop of radius R?
Hint: Direction is given by the Right-Hand Thumb Rule.
Answer
B = (μ₀ I) / (2R) For an N-turn coil: B = (μ₀ N I) / (2R)
Card 3 of 22
State Ampere's Circuital Law.
Hint: Analogous to Gauss's Law in electrostatics.
Answer
The line integral of the magnetic field B around any closed path in free space is equal to μ₀ times the total current passing through the surface enclosed by the closed path.
Card 4 of 22
What is the Magnetic Field (B) at a distance 'r' from an infinitely long straight current-carrying wire?
Hint: The magnetic field lines form concentric circles around the wire.
Answer
B = (μ₀ I) / (2πr)
Card 5 of 22
Write the formula for the Magnetic Field (B) deep inside a long, tightly wound Solenoid.
Hint: At the ends of the solenoid, the magnetic field is exactly half of the field at the center: B_end = (μ₀ n I) / 2.
Answer
B = μ₀ n I Where 'n' is the number of turns per unit length (n = N/L).
Card 6 of 22
Write the expression for the Lorentz Force experienced by a charge 'q' moving with velocity 'v' in both Electric (E) and Magnetic (B) fields.
Hint: If v is parallel to B, the magnetic force is zero.
Answer
Answer Given Below:
Card 7 of 22
What is the radius (r) of the circular path taken by a charge 'q' moving perpendicular to a uniform magnetic field 'B'?
Hint: Derived from equating centripetal force to magnetic force: mv²/r = qvB.
Answer
r = (mv) / (qB) = p / (qB) Where 'm' is mass, 'v' is velocity, and 'p' is momentum.
Card 8 of 22
What is the Time Period (T) of a charged particle moving in a uniform magnetic field?
Hint: Notice that Time Period and Frequency are INDEPENDENT of the velocity (v) and radius (r) of the particle!
Answer
T = (2πm) / (qB) Frequency (Cyclotron frequency) f = (qB) / (2πm)
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