Atmospheric pressure at sea level is 1.013×10⁵ Pa. Equivalent height of mercury column (density 13600 kg/m³, g=9.8) is MCQ with Answer and Explanation

Explanation:
Potentiometer sensitivity (ability to detect small EMF changes) increases with longer wire because potential gradient (V/cm) decreases, allowing finer measurement of balancing length. Sensitivity ∝ length of wire. Decreasing length (B) reduces sensitivity; increasing current (C) increases potential gradient, reducing sensitivity; thicker wire (D) reduces resistance but doesn't directly affect sensitivity if current adjusted. Memory tip: 'Longer potentiometer wire ⇒ smaller potential gradient ⇒ higher sensitivity'. This experimental physics concept is frequently tested in competitive exams. Always link sensitivity to potential gradient: smaller gradient allows detection of smaller voltage differences.

Explanation:
Kepler's laws of planetary motion. Newton explained them via gravitation.

Explanation:
Rutherford's gold foil experiment led to planetary model: electrons revolve around tiny positive nucleus. Bohr added quantized orbits. Thomson proposed plum-pudding model. Dalton atomic theory earlier.