The wavelength of ultrasonic waves is MCQ with Answer and Explanation

Explanation:
Convex mirrors bulge outwards, which inherently provides a much wider field of view compared to plane mirrors. Regardless of the object's position, a convex mirror reliably produces virtual, erect, and diminished (smaller) images. This allows a driver to see a large area of the road behind them in a small mirror, making R the exact explanation for A.

Explanation:
Rules: leading zeros not significant; trailing zero after decimal is significant. Digits 4,0,5,0 are significant ⇒ 4 sig figs. Memory tip: 'Start at first non-zero; include trailing zeros after decimal'. Measurement precision concept frequently tested in competitive exams.

Explanation:
Oil immersion increases numerical aperture (NA) by matching refractive indices, improving resolution d = λ/(2NA). Memory tip: 'Higher NA or shorter λ ⇒ better resolution'. Optical instrument concept frequently tested in competitive exams.