The work done in moving a charge of 2 C between two points with potential difference of 12 V is:
A. 24 J
B. 6 J
C. 14 J
D. 0.167 J
Answer: Option A
Solution (By JKSSB Mock Tests)
Work done W = charge (Q) × potential difference (V). Thus W = 2 C × 12 V = 24 J. This follows from definition of voltage: 1 volt = 1 joule per coulomb. The work done equals the change in electrical potential energy. This fundamental relationship is crucial in electricity. Memory tip: W = QV is analogous to mechanical work = force × distance. Such direct formula applications are common in competitive exams to test basic concept retention. Always verify units: coulomb × volt = joule, confirming dimensional consistency.
Explanation:
Resolving power is a telescope's ability to distinguish closely spaced objects (like double stars) as separate. It is proportional to D / lambda, where D is the diameter (aperture) of the objective lens and lambda is the wavelength of light. Increasing the aperture D directly and strictly increases the resolving power.
Explanation:
Motor converts electrical to mechanical energy using force on a current-carrying conductor in magnetic field (F = BIL). Electromagnetic induction is for generator. Motor principle: A current-carrying coil experiences torque in magnetic field.
Explanation:
Speed of light ≈ 3×10⁸ m/s, sound ≈ 340 m/s. Light reaches almost instantly, sound takes time. So thunder heard after lightning. Time delay gives distance: d = v_sound × t.
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