NEET Physics: angular momentum Practice Questions
15 free multiple-choice questions on angular momentum (Rotational Motion) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which condition must be met for the angular momentum of a system to be conserved?
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Correct answer: A — The net external torque acting on the system is zero
Angular momentum is conserved if and only if the net external torque acting on the system is zero (τₙₑₜ = 0).
Q2. Which physical quantity is the rotational analogue of linear momentum?
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Correct answer: C — Angular momentum
Angular momentum is the rotational analogue of linear momentum. While linear momentum is mass times velocity (p=mv), angular momentum is related to the distribution of mass and the rotational motion of the body.
Q3. For a particle, angular momentum is conserved if the net external torque acting on it is:
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Correct answer: B — zero
According to the rotational equivalent of Newton's second law, the rate of change of angular momentum is equal to the net external torque (τ). Therefore, angular momentum is conserved only when the net external torque is zero.
Q4. Angular momentum is conserved only when the net external torque acting on the system is:
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Correct answer: D — Zero
According to the rotational impulse-momentum theorem, angular momentum is conserved if and only if the net external torque (τₙₑₜ) acting on the system is zero.
Q5. In a closed system where no external net torque acts on the system, the total angular momentum of the system must be:
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Correct answer: C — Zero or conserved
According to the principle of conservation of angular momentum, if the net external torque acting on a system is zero, the total angular momentum of the system remains constant (conserved).
Q6. Angular momentum is conserved if the net external torque acting on the system is:
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Correct answer: B — zero
According to the rotational analog of Newton's second law, the net external torque (τ) is equal to the rate of change of angular momentum (dL/dt). If there is no net external torque (τ=0), the angular momentum (L) remains constant (conserved).
Q7. The unit of angular momentum in SI units is:
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Correct answer: B — kg⋅m/s
Angular momentum (L) is calculated as the product of the moment of inertia and angular velocity, or r × p. The SI unit is kg⋅m²/s (or J⋅s), which is equivalent to kg⋅m²/s, or kg⋅m²/s in the context of L = Iω. In rotational motion, it is often expressed in J⋅s, which is equivalent to kg⋅m²/s.
Q8. If the mass of a rotating body is doubled while its radius remains unchanged, how does its moment of inertia change?
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Correct answer: A — It is doubled
The moment of inertia I = 1/2MR². Since M is doubled and R is constant, I is doubled.
Q9. The unit of angular momentum in the SI system is:
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Correct answer: D — kg·m/s
Angular momentum is defined as the product of the moment of inertia and angular velocity (L=Iω). The unit is kg·m²/s² · rad = kg·m²/s or J·s (Joule-second).
Q10. If the angular velocity of a rotating object is doubled while its moment of inertia remains unchanged, what happens to its angular momentum?
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Correct answer: C — It is doubled
Angular momentum (L) is given by L = Iω. If I is constant and ω is doubled, the angular momentum L must also be doubled.
Q11. The rotational form of the linear momentum equation, p = mv, is L = Iω. Here, I represents the moment of inertia and ω represents the angular velocity. Which physical quantity has the same dimensional nature as angular momentum (L)?
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Correct answer: B — Linear Momentum
Angular momentum (L) is mathematically equivalent to the product of the moment of inertia (I) and angular velocity (ω). Since I is the rotational analogue of mass, and ω is the rotational analogue of velocity, angular momentum has the same dimensions as linear momentum (mv).
Q12. If the moment of inertia of a rotating object is doubled while its angular velocity remains the same, how does its angular momentum change?
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Correct answer: B — It is doubled
Angular momentum L = Iω. If I is doubled and ω is constant, the angular momentum L is doubled.
Q13. The angular momentum (L) of a rotating body is defined by the product of its moment of inertia (I) and its angular velocity (ω). If the moment of inertia of a body is doubled while its angular velocity remains unchanged, the new angular momentum will be:
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Correct answer: B — Doubled
Angular momentum L = Iω. If I is doubled (2I) and ω remains the same, the new angular momentum L' = (2I)ω= 2(Iω) = 2L. Thus, the angular momentum is doubled.
Q14. If a body rotates with a constant angular velocity, its angular momentum is directly proportional to:
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Correct answer: A — The moment of inertia
Angular momentum L = Iω. Since ω is constant, L is directly proportional to the moment of inertia (I).
Q15. A body's moment of inertia is inversely proportional to which physical property?
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Correct answer: B — Angular Velocity
The moment of inertia (I) depends on the mass distribution relative to the axis. While L=Iω, I is intrinsically linked to how mass is distributed, which relates to angular velocity in dynamic situations. (In simple conceptual recall, I relates mass distribution, which is key to L conservation).
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