The change in momentum of a body is equal to MCQ with Answer and Explanation

Explanation:
Photovoltaic effect: photons excite electrons in semiconductor, creating voltage. Direct light-to-electricity conversion. Memory tip: 'Photo = light; voltaic = electricity'. Renewable energy principle frequently tested in competitive exams to assess energy conversion understanding.

Explanation:
The seven fundamental SI units are: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), and candela (cd). Candela is the unit of luminous intensity. Newton, joule, and pascal are derived units. Newton = kg·m/s², joule = kg·m²/s², pascal = kg/(m·s²). Hence, candela is a fundamental unit. Exam tip: Remember the acronym ‘MKS A K M C’ for the seven base units.

Explanation:
Sublimation: solid → gas. Example: dry ice (CO₂), camphor. Deposition is reverse (gas → solid). Melting solid → liquid, evaporation liquid → gas.