The relation V = IR is applicable to MCQ with Answer and Explanation

Explanation:
Beats occur when two sound waves of slightly different frequencies interfere, causing periodic variation in amplitude (loudness). Beat frequency = |f₁ - f₂|. This is a superposition/interference phenomenon. Reflection, refraction, diffraction don't produce beats. Memory tip: 'Beats = interference of close frequencies; used in tuning instruments'. This conceptual question tests wave superposition understanding, frequently examined in competitive exams. Always distinguish beats (amplitude modulation) from resonance (amplitude increase at natural frequency).

Explanation:
Cadmium or boron absorb neutrons to control chain reaction.

Explanation:
Gamma rays are photons, electromagnetic waves with wavelengths shorter than X-rays, produced in nuclear transitions. No mass, no charge. Highly penetrating. Stopped by thick lead.