The working principle of a hydrogen bomb is MCQ with Answer and Explanation

Explanation:
For a body at rest, displacement remains constant over time. The displacement-time graph is a horizontal line, parallel to time axis, indicating zero slope (velocity = 0). Option A indicates constant velocity. Option B (velocity-time zero slope) means constant velocity, not necessarily rest (could be constant non-zero velocity). Option D indicates acceleration. So C is correct.

Explanation:
Dispersion happens because refractive index varies with wavelength. Prism, rainbow. Scattering is Tyndall effect (blue sky). Polarisation restricts vibrations.

Explanation:
When a wave (like light or sound) changes mediums, its velocity changes due to the new medium's optical or mechanical density. Wavelength changes proportionally with velocity (v = fλ). However, frequency is determined solely by the source generating the wave and the energy of the photons/particles, and it remains absolutely constant.