A current of 2 A flows through a 10 Ω resistor for 1 minute. Heat produced is MCQ with Answer and Explanation

Explanation:
Resistance R = ρL/A. Volume V = A·L constant. If L' = 2L, then A' = V/L' = V/(2L) = A/2. Thus R' = ρ(2L)/(A/2) = 4(ρL/A) = 4R. Resistance increases by factor of 4. Memory tip: 'Stretching wire: R ∝ L² when volume constant'. This proportional reasoning problem tests resistance concepts, frequently appearing in competitive exams. Always verify volume conservation assumption; if area changed independently, result would differ. This problem assesses understanding of geometric effects on electrical properties.

Explanation:
Emission requires photon energy hν ≥ work function φ ⇒ ν ≥ ν₀. Intensity affects electron count, not emission possibility. Memory aid: 'Photoelectric: frequency threshold (quantum); intensity affects current'. Quantum physics concept frequently tested in competitive exams.

Explanation:
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