Skip to content
Login Register

#exam question

518 public questions tagged with this topic.

Fluid Pressure, Pascal's Law and Manometers

Which of the following statements is correct about viscosity?

Viscosity measures a fluid’s resistance to flow due to internal friction between layers, decreasing with temperature in liquids as cohesive forces weaken, not increasing. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It measures resistance to flow. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Conservation of Angular Momentum

A force F\=5i^+4j^N acts at r\=−3i^−2j^m. What is the magnitude of the torque about the origin?

τ = r×F = |i^j^k^−3−20540| = k^((−3)×4−(−2)×5) = k^(−12+10) = −2k^Nm. Magnitude = 2Nm. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2 Nm. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Conservation of Angular Momentum

Why does a body with zero net torque maintain its rotational state?

Zero net torque (τ = 0) means no change in angular momentum (dLdt = 0), so the rotational state (angular velocity) remains constant. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Due to no change in angular momentum. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Conservation of Angular Momentum

A 2kg mass rotates in a circle of radius 0.5m with a speed of 8m/s. What is its angular momentum about the center?

L = mvr. m = 2kg, v = 8m/s, r = 0.5m. L = 2×8×0.5 = 8kg m2/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 8.0 kg m²/s. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Conservation of Angular Momentum

A thin ring of mass 1kg and radius 0.2m rotates about its center. If its kinetic energy is 4J, what is its angular speed

KE: K = 12Iω2. For a ring: I = MR2 = 1×(0.2)2 = 0.04kg m2. 4 = 12×0.04×ω2⇒8 = 0.04ω2⇒ω2 = 200⇒ω = 200≈14.14rad/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 14 rad/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Conservation of Angular Momentum

In rotational dynamics, what role does torque play?

Torque causes angular acceleration, as per τ = Iα, analogous to how force causes linear acceleration in Newton’s second law. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It causes angular acceleration. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

View Details
Energy of Satellites and Binding Energy

Which of the following statements is incorrect about gravitational potential energy?

It’s negative (option 1 correct), zero at infinity (option 2 correct), and conservative (option 3 correct). Option 4 is incorrect as it depends on distance, not mass alone. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It depends only on mass. This satisfies dimensional consistency and physical conditions given, so option D is scientifically correct.

Ref: Halliday & Resnick, Fundamentals of Physics, 11th ed., Chapter 13: Gravitation.

View Details
Orbital Velocity and Time Period

Which of the following statements is correct about gravitational potential energy?

V = −GMmr is defined with zero at infinity, and work is needed to separate masses, making option 2 correct. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It is zero at infinite separation. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: Halliday & Resnick, Fundamentals of Physics, 11th ed., Chapter 13: Gravitation.

View Details