A pump lifts 100 kg of water through 5 m in 2 s. Power (g=10) is MCQ with Answer and Explanation

Explanation:
Newton's law of gravitation: F ∝ 1/r². If distance r becomes r/2, new force F' ∝ 1/(r/2)² = 4/r² = 4F. So force quadruples. This inverse square law is fundamental for gravitational, electric, magnetic forces.

Explanation:
Photon energy E = hν, where h is Planck's constant, ν is frequency. Thus E ∝ ν. Since c = νλ, E = hc/λ, so E ∝ 1/λ (inversely proportional to wavelength). Amplitude relates to intensity (number of photons), not individual photon energy. Speed is constant (c) in vacuum. Memory aid: 'Higher frequency (shorter wavelength) photons have more energy (e.g., gamma > radio)'. This quantum physics concept is frequently tested in competitive exams. Always use E = hν for photon energy calculations; avoid confusing wave amplitude with photon energy.

Explanation:
The pitch of a sound is a subjective sensation that is determined primarily by the frequency of the sound wave. Higher frequency waves are perceived as high-pitched sounds (like a whistle), while lower frequency waves are perceived as low-pitched sounds (like a bass drum). Amplitude determines the loudness of the sound.