The resolving power of a microscope is increased by: MCQ with Answer and Explanation

Resolving power (minimum resolvable distance) d = λ/(2NA), where NA is numerical aperture. Oil immersion increases NA by matching refractive index between slide and objective, reducing light refraction and increasing light collection. Longer wavelength (A) decreases resolving power; decreasing NA (C) worsens resolution; magnification (D) doesn't affect fundamental resolution limit. Memory aid: 'Higher NA or shorter λ ⇒ better resolution'. This application question tests optical instrument knowledge, common in competitive exams. Always link resolution to wave nature of light (diffraction limit) and instrument design factors.