The dimension of Planck's constant is same as that of
A. Energy
B. Linear momentum
C. Angular momentum
D. Force
Answer: Option C
Solution (By JKSSB Mock Tests)
Planck's constant h = E/ν, so its dimensions are [Energy]/[Frequency] = [ML²T⁻²]/[T⁻¹] = [ML²T⁻¹]. Angular momentum = mvr = M·LT⁻¹·L = [ML²T⁻¹]. Energy = [ML²T⁻²], linear momentum = [MLT⁻¹], force = [MLT⁻²]. Thus, Planck's constant and angular momentum share dimensions. This is a key dimensional match in quantum mechanics.
Explanation:
Air has mass, gravity pulls it, creating weight. Pressure at any point is weight of air column above per unit area. At sea level ~10⁵ Pa. Decreases with altitude.
Explanation:
Work done is given by W = F * d * cos(theta). In uniform circular motion, the centripetal force is always directed strictly towards the center of the circle, while the instantaneous displacement (velocity vector) is tangential to the circle. The angle (theta) between them is exactly 90 degrees. Since cos(90) = 0, the work done by the centripetal force is always zero.
Explanation:
Convex lens: object within focal length (u < f) produces virtual, erect, magnified image (magnifying glass). Beyond F: real images. Memory tip: 'Convex lens: u < f ⇒ virtual image; u > f ⇒ real image'. Ray optics concept frequently tested in competitive exams to verify lens image formation rules.
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