The energy of a photon is directly proportional to its: MCQ with Answer and Explanation

Explanation:
Longer wire ⇒ smaller potential gradient (V/cm) ⇒ finer voltage measurement ⇒ higher sensitivity. Memory tip: 'Sensitivity ∝ wire length; smaller gradient = better resolution'. Experimental physics concept frequently tested in competitive exams.

Explanation:
Wave speed v = fλ = 50 × 0.6 = 30 m/s. Basic wave equation. Ensure consistent units: frequency Hz (s⁻¹), wavelength m. Speed of sound 340 m/s in air, this is slower.

Explanation:
Fringe width β = λD/d, where λ wavelength, D screen distance, d slit separation. New d' = 2d, new D' = D/2. Thus β' = λ(D/2)/(2d) = λD/(4d) = β/4. Fringe width reduces to one-fourth. Memory tip: 'β ∝ D/d; changes multiply'. This proportional reasoning problem tests wave optics understanding, frequently appearing in competitive exams. Always track how each parameter change affects the result; combine multiplicative factors for net effect. Verify with dimensional analysis: β has length dimension, consistent with λD/d.