Magnetic field around straight current-carrying wire is:
A. Radial
B. Uniform
C. Circular concentric
D. Parallel to wire
Answer: Option C
Solution (By JKExamLibrary)
Biot-Savart law: field forms concentric circles around wire, direction by right-hand thumb rule. Magnitude B = μ₀I/(2πr), decreasing with distance. Memory tip: 'Right-hand rule: thumb = current, fingers = field circles'. Fundamental magnetism concept frequently tested in competitive exams.
Explanation:
Acceleration a = dv/dt = d(3t² + 2t)/dt = 6t + 2. At t = 2 s: a = 6(2) + 2 = 14 m/s². Differentiation of velocity gives instantaneous acceleration. Memory tip: a = dv/dt; for polynomial v(t), differentiate term by term. Tests calculus application in kinematics, common in advanced competitive exam questions.
Explanation:
Electric fields deflect charged particles via Coulomb forces (F=qE), and magnetic fields deflect moving charged particles via Lorentz forces (F=qvB). Gamma rays are purely high-energy electromagnetic photons. Because they lack any electrical charge (q=0), both electric and magnetic forces on them are exactly zero. Therefore, they pass through fields completely un-deflected. R explains A perfectly.
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