If the radius of the earth shrinks by 1%, its mass remaining the same, the value of 'g' on the earth's surface would:
A. Increase by 2%
B. Increase by 1%
C. Decrease by 2%
D. Decrease by 1%
Answer: Option A
Solution (By JKSSB Mock Tests)
The acceleration due to gravity is given by g = GM/R². For a small change, taking the derivative or using error approximation: Δg/g = -2(ΔR/R). If R shrinks by 1% (ΔR/R = -1%), then Δg/g = -2(-1%) = +2%. Therefore, the value of 'g' will increase by approximately 2%.
According to Brewster's Law, when unpolarized light is incident on a transparent medium at the polarizing angle (Brewster's angle), the reflected and refracted rays are:
Explanation:
Brewster's Law states that when light hits a dielectric boundary at a specific angle of incidence (Brewster's angle, theta_p), the reflected light is completely plane-polarized. At this exact geometric condition, the angle between the reflected ray and the refracted (transmitted) ray is strictly 90 degrees.
Explanation:
Spectrometer uses diffraction grating/prism to disperse light and measure wavelengths via angular positions. Memory tip: 'Spectrometer = wavelength via dispersion; used in spectroscopy'. Instrument application frequently tested in competitive exams.
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