Which of the following is an application of electromagnetic induction? MCQ with Answer and Explanation

Explanation:
Newton's third law states: for every action, there is an equal and opposite reaction. These forces act on two different interacting bodies, hence they never cancel each other as they don't act on the same body. They can act at a distance (e.g., gravitational forces) or through contact. Cancellation of forces occurs only when multiple forces act on a single body. This distinction is crucial for free-body diagram analysis. Exam tip: Always identify which body each force acts upon. Misconception about force cancellation is a common trap in competitive exam questions testing Newton's laws.

Explanation:
Doppler effect: apparent frequency change due to relative motion. Approaching increases frequency.

Explanation:
Surface tension = force/length. Force dimensions [MLT⁻²], length [L], so [MLT⁻²]/[L] = [MT⁻²]. Also energy per area gives same dimensions: [ML²T⁻²]/[L²] = [MT⁻²].