The device used to measure electric potential difference is MCQ with Answer and Explanation

Explanation:
2.50 has three significant digits. Trailing zero after decimal significant because least count 0.01.

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:
Objects float if their density is less than the fluid. Cork density < water density, so it floats. Iron sinks because density > water. Ship made of iron floats due to shape displacing more water, average density less.