15 public questions tagged with this topic.
The resultant viscosity depends on the nature of the solute correct as per chemistry principle.
Ref: NCERT Chemistry Class XII — Solutions
Stokes’ law ( F = 6 π eta a v ) shows that viscous force is proportional to radius ( a ), while weight ( 4/3 π a³ rho g ) depends on a³ . At terminal velocity, these balance, making v propto a² .
Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.
Higher temperatures increase molecular kinetic energy in liquids, weakening intermolecular forces, reducing resistance to flow, and thus lowering viscosity, as noted in the chapter. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Intermolecular forces weaken. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Viscosity causes internal friction between fluid layers, converting kinetic energy into heat through shear stress, leading to energy dissipation, which Bernoulli’s ideal flow neglects. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It converts kinetic energy to heat. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Fluids lack rigidity and cannot resist shear stress without flowing. Any attempt to apply shear stress causes deformation (flow), as fluids have no fixed shape, unlike solids, which resist shear due to strong intermolecular forces.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Stokes’ law: F = 6πηav. η = 0.2Pa s, a = 0.04m, v = 0.12m/s. F = 6×3.14×0.2×0.04×0.12 = 0.1809N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.18 N. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Viscous force: F = ηvAl. η = 0.83Pa s, v = 0.8m/s, A = 0.08m2, l = 0.7×10−3m. F = 0.83×0.8×0.080.7×10−3 = 0.83×91.43 = 75.89N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 76 N. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Viscous force: F = ηvAl. η = 1.0×10−3Pa s, v = 0.7m/s, A = 0.05m2, l = 0.8×10−3m. F = 1.0×10−3×0.7×0.050.8×10−3 = 1.0×10−3×43.75 = 0.04375N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.044 N. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
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.
Viscous force: F = ηvAl. η = 0.113Pa s, v = 0.6m/s, A = 0.07m2, l = 0.9×10−3m. F = 0.113×0.6×0.070.9×10−3 = 0.113×46.67 = 5.27N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 5.3 N. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Bernoulli’s principle assumes no energy loss due to friction, which is valid for non-viscous fluids. High viscosity causes frictional losses between fluid layers, converting kinetic energy into heat, thus violating the energy conservation assumption.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
Viscous force: F = ηvAl. η = 1.0×10−3Pa s, v = 0.5m/s, A = 0.09m2, l = 1.0×10−3m. F = 1.0×10−3×0.5×0.091.0×10−3 = 1.0×10−3×45 = 0.045N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.045 N. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.
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