Stefan-Boltzmann Law states that the total radiant heat energy emitted from a perfectly black body is proportional to: MCQ with Answer and Explanation

Explanation:
Endoscopes consist of bundles of flexible optical fibers. Light introduced at one end is trapped inside the fiber core because it repeatedly strikes the boundary at an angle greater than the critical angle. This Total Internal Reflection allows light and visual images to be transmitted through complex, curving paths inside the body.

Explanation:
Joule's law states that heat produced H = I²Rt, where I is current, R resistance, t time. This quantifies electrical energy converted to thermal energy in resistors. Ohm's law relates V, I, R; Faraday's and Lenz's laws concern electromagnetic induction. Memory aid: 'Joule heating ∝ I²R'. This definition-based question tests knowledge of fundamental laws in electricity, commonly examined in competitive exams. Applications include electric heaters, fuses, and incandescent bulbs. Always distinguish Joule's law (heating) from power formulas (P=VI=I²R=V²/R).

Explanation:
Wavelength is distance between successive crests or successive troughs.