A wooden block floats with half its volume submerged in water. Density of wood is MCQ with Answer and Explanation

Explanation:
When light crosses media, frequency remains constant as it's determined by the source. Speed and wavelength change proportionally: v = fλ, and v = c/n, so λ decreases in denser medium (glass). Amplitude may change due to reflection/transmission coefficients. Memory aid: 'Frequency is source-dependent; speed and wavelength are medium-dependent'. This fundamental wave property is frequently tested in refraction questions. Competitive exams often use this to assess understanding of wave behavior at interfaces. Always recall that color (frequency) doesn't change during refraction, though speed and wavelength do.

Explanation:
Maxwell's Right-Hand Thumb Rule states that if you imagine holding a straight current-carrying conductor in your right hand such that the thumb points in the direction of the current, then the direction in which your fingers wrap around the conductor represents the direction of the circular magnetic field lines.

Explanation:
g decreases with depth: g' = g(1 - d/R). At centre d=R, g'=0. Weightless at centre. At poles g=9.83, equator 9.78. At surface it's maximum.