Capacitor energy U = ½CV². If voltage doubled, energy becomes: MCQ with Answer and Explanation
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Question #1
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Which of the following is NOT a fundamental SI unit?
Correct Answer: Option B
Explanation:
Coulomb is the SI unit of electric charge, but it is a derived unit (Ampere × second). The seven fundamental SI units are meter (length), kilogram (mass), second (time), Kelvin (temperature), Ampere (electric current), candela (luminous intensity), and mole (amount of substance). Electric current is fundamental, making Ampere fundamental, not Coulomb.
Coulomb is the SI unit of electric charge, but it is a derived unit (Ampere × second). The seven fundamental SI units are meter (length), kilogram (mass), second (time), Kelvin (temperature), Ampere (electric current), candela (luminous intensity), and mole (amount of substance). Electric current is fundamental, making Ampere fundamental, not Coulomb.
Question #2
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The power of a lens is +2 D. Its focal length is
Question #3
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The frequency of a sound wave determines its:
Correct Answer: Option C
Explanation:
Frequency determines pitch: higher frequency ⇒ higher pitch (e.g., whistle vs drum). Loudness depends on amplitude; quality (timbre) on waveform/harmonics; speed on medium properties (density, elasticity). This is a fundamental characteristic of sound perception. Memory aid: 'Frequency → Pitch; Amplitude → Loudness'. Competitive exams often test these distinctions to identify misconceptions. Note: Speed of sound is independent of frequency in a given medium (non-dispersive for audible sound in air). Always link physical quantities to perceptual attributes correctly.
Frequency determines pitch: higher frequency ⇒ higher pitch (e.g., whistle vs drum). Loudness depends on amplitude; quality (timbre) on waveform/harmonics; speed on medium properties (density, elasticity). This is a fundamental characteristic of sound perception. Memory aid: 'Frequency → Pitch; Amplitude → Loudness'. Competitive exams often test these distinctions to identify misconceptions. Note: Speed of sound is independent of frequency in a given medium (non-dispersive for audible sound in air). Always link physical quantities to perceptual attributes correctly.
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