A piece of ice of density 0.9 g/cm³ floats in water. Fraction of volume above water is MCQ with Answer and Explanation

Explanation:
Viscosity η = Force/(Area × velocity gradient). Force [MLT⁻²], area [L²], velocity gradient [T⁻¹]. So η = [MLT⁻²]/([L²][T⁻¹]) = [ML⁻¹T⁻¹]. Often asked.

Explanation:
Doppler effect: apparent frequency change due to relative motion. Approaching increases frequency.

Explanation:
Heat flows until temperatures equal, i.e., thermal equilibrium. Not necessarily 50°C unless heat capacities equal.