The dimension of Planck's constant is same as that of MCQ with Answer and Explanation

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.

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Practice More Physics Questions

Question #1
The atmosphere exerts pressure because
A. Air is moving
B. Air is weightless
C. Air is hot
D. Air has mass and is attracted by gravity

Correct Answer: Option D


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.

This question belongs to: Science Physics
Question #2
When a body is moving in a uniform circular motion, the work done by the centripetal force is zero because:
A. The body has no kinetic energy.
B. The force is balanced by an outward centrifugal force.
C. The force is extremely weak.
D. The force is always perpendicular to the instantaneous displacement.

Correct Answer: Option D


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.

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Question #3
Convex lens forms virtual image when object is:
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B. Within focal length
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D. Beyond 2F

Correct Answer: Option B


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.

This question belongs to: Science Physics