Which of the following colors of light has the lowest frequency?
A. Red
B. Blue
C. Violet
D. Green
Answer: Option A
Solution (By JKSSB Mock Tests)
In the visible spectrum (VIBGYOR), wavelength increases from Violet to Red. Since speed = frequency × wavelength (c = fλ), frequency is inversely proportional to wavelength. Red light has the longest wavelength and therefore the lowest frequency and lowest energy. Violet has the shortest wavelength and highest frequency.
Explanation:
Myopia (nearsightedness) is the inability to see distant objects clearly, with far point less than infinity. Here, far point is 2 m. Corrected using concave lens. Hypermetropia (farsightedness) affects near vision; presbyopia is age-related loss of accommodation; astigmatism involves uneven corneal curvature. Memory aid: 'Myopia = near-sighted; far point reduced'. This application question tests knowledge of vision defects and corrections, frequently appearing in competitive exams. Always link symptom (blurred distant vision) to defect (myopia) and correction (diverging lens).
Explanation:
Generator: coil rotated in magnetic field induces emf. Motor: opposite. Transformer: changes voltage, no moving parts. Rectifier: AC to DC.
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