The change in momentum of a body is equal to MCQ with Answer and Explanation

Explanation:
A liquid drop has only one free surface, so its excess pressure is P = 2T/R. However, a soap bubble in the air has two completely free surfaces (an inner one and an outer one). Because both surfaces exert surface tension forces inward, the total excess pressure inside a soap bubble is exactly double: P = 4T/R.

Explanation:
Werner Heisenberg, a German theoretical physicist, published his famous Uncertainty Principle in 1927. The principle dictates a fundamental limit to precision at the quantum level: the more precisely the position of a particle (like an electron) is determined, the less precisely its momentum can be known, and vice versa. Mathematically, delta_x * delta_p >= h/(4pi).

Explanation:
Potentiometer uses null method: at balance, no current flows through cell, so measured voltage equals true EMF (no internal resistance drop). Memory aid: 'Null method ⇒ zero current ⇒ accurate EMF measurement'. Experimental physics concept frequently tested in competitive exams to verify understanding of precision measurement techniques.