A body of mass 4 kg is raised from height 2 m to 8 m. Increase in potential energy (g=10) is MCQ with Answer and Explanation

Explanation:
R ∝ L/A. New L'=2L, A'=A/2 => R' = ρ(2L)/(A/2) = 4ρL/A = 4R. Alternatively, volume constant? Not given, here both changed independently. So 4R.

Explanation:
Energy density = energy/volume. Energy has dimensions [ML²T⁻²], volume [L³], so energy density = [ML²T⁻²]/[L³] = [ML⁻¹T⁻²]. Pressure = force/area = [MLT⁻²]/[L²] = [ML⁻¹T⁻²], identical. Force is [MLT⁻²], power [ML²T⁻³], momentum [MLT⁻¹]. This equivalence explains why pressure appears in Bernoulli's equation alongside kinetic/potential energy density. Memory aid: 'Pressure and energy density share dimensions [ML⁻¹T⁻²]'. This dimensional analysis question tests ability to derive and compare formulas, frequently appearing in competitive exams to assess conceptual depth.

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.