36 public questions tagged with this topic.
The Kelvin scale is offset from the Celsius scale by 273.15, so T = tC+273.15 (Section 10.4), where T is Kelvin and tC is Celsius. As per NCERT, applying relevant law/formula with correct units and sign convention leads to T\=tC+273.15. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
In calorimetry (Section 10.7), heat lost by the hot object equals heat gained by the water and calorimeter at thermal equilibrium, where no further heat transfer occurs. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Heat lost equals heat gained. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.
Heating the metal lid causes it to expand due to thermal expansion, loosening its grip on the jar, which expands less if made of glass or remains unchanged if plastic.
Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.
The equation of continuity (Av = constant) for an incompressible fluid in steady flow implies that as the cross-sectional area decreases, the velocity must increase to maintain a constant mass flow rate.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Torricelli’s law (v = 2gh) shows that the efflux speed depends only on depth, remaining constant near the hole until external factors (e.g., air resistance or gravity’s vertical effect) alter its trajectory.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Surface tension arises from cohesive forces between liquid molecules, creating a contractile force at the surface, resembling a stretched membrane that resists expansion, as molecules at the surface have higher energy than those inside.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Mercury’s high density (13.6×103kg/m3) results in a shorter column height (h = Pa/ρg) to balance atmospheric pressure, making it more practical than water, which requires a much taller column due to lower density.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Pressure increases with depth due to the weight of the fluid column above, as given by P = ρgh. The greater the depth, the more fluid mass contributes to the pressure at that point.
Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.
Surface tension minimizes surface energy by reducing surface area. For a given volume, a sphere has the smallest surface area, making it the preferred shape for liquid drops when gravity or other forces are negligible.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
A barometer measures atmospheric pressure by balancing it with the weight of a liquid column (Pa = ρgh), typically mercury due to its high density, which shortens the column height.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
The Magnus effect causes a spinning object to deviate due to a pressure difference from varying air speeds (Bernoulli’s principle), not viscosity or gravity alone. The incorrect statement is that it’s due to gravitational force.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Terminal velocity (v∝(mg−Fb)/6πηa) depends on weight minus buoyant force. A heavier object has a greater net downward force, increasing its terminal velocity compared to a lighter object of the same size.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
