Work per unit charge to move between points is: MCQ with Answer and Explanation

Explanation:
Polarization (restriction of electric field oscillation to one plane) is possible only for transverse waves, where oscillations are perpendicular to propagation direction. Longitudinal waves (e.g., sound) cannot be polarized as oscillations are along propagation. This was key evidence for light's transverse wave nature. Memory aid: 'Polarization ⇒ transverse wave; light is EM transverse wave'. This conceptual question tests wave optics fundamentals, frequently examined in competitive exams. Always distinguish wave types: transverse (light, string waves) vs longitudinal (sound, spring waves).

Explanation:
Vernier caliper is ideal for measuring internal diameters of narrow tubes due to its internal jaws designed for such measurements. Screw gauge measures external dimensions like wire diameter. Meter scale and measuring tape lack the precision (least count ~1 mm) needed for narrow tubes. Vernier calipers typically have least count 0.01 mm or 0.02 mm. Practical tip: Always use internal jaws for internal measurements, external jaws for outer dimensions. This application-based question tests knowledge of instrument selection in experimental physics, commonly featured in practical examination sections.

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.