A student measures the length of a rod as 3.50 cm using a vernier caliper with least count 0.01 cm. The number of significant figures in this measurement is: MCQ with Answer and Explanation

Explanation:
Floatation: weight = buoyant force ⇒ ρ_obj·V·g = ρ_liq·V_sub·g ⇒ ρ_obj/ρ_liq = V_sub/V = 0.4. Fraction submerged equals density ratio. Memory tip: 'Submerged fraction = ρ_object/ρ_fluid'. Direct Archimedes' principle application frequently tested in buoyancy sections of competitive exams.

Explanation:
Minimum deviation δ_m for a prism: n = sin[(A + δ_m)/2] / sin(A/2), where A is prism angle, n refractive index. Thus δ_m depends on both A and n. Since n varies with wavelength (dispersion), δ_m also depends on wavelength, but the primary dependencies are A and n. Memory tip: 'δ_m increases with A and n; used to measure n'. This optics formula application is frequently tested in competitive exams. Always recall that minimum deviation occurs when ray passes symmetrically through prism, a key condition for derivation.

Explanation:
Diode has non-linear I-V characteristic. Metals are ohmic.