The resolving power of a microscope is increased by:
A. Using oil immersion
B. Reducing the magnification
C. Using light of longer wavelength
D. Decreasing the numerical aperture
Answer: Option A
Solution (By JKSSB Mock Tests)
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.
Explanation:
1 kWh = 1000 W × 3600 s = 3,600,000 J = 3.6 × 10⁶ J. This is a standard conversion. Power (watt) × time (hour) gives energy. 1 watt = 1 J/s. Remember this for electricity bills.
Explanation:
First law of thermodynamics: Energy is conserved in an isolated system. It changes forms (kinetic to potential etc.) but total constant. Perpetual motion machine impossible.
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