23 public questions tagged with this topic.
Viruses are considered living only when inside a host ll, where they use the host’s machinery to replicate. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
ve = 2GMR decreases with altitude as R+h increases, making option 4 correct. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It decreases with altitude. 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.
An object escapes if its total mechanical energy (E = KE+PE) is zero or positive. This occurs when its initial speed equals or exceeds the escape speed (ve = 2GMR), making energy the key factor.
Ref: Halliday & Resnick, Fundamentals of Physics, 11th ed., Chapter 13: Gravitation.
V = −GMmr, which is negative for bound systems and decreases (becomes more negative) as r decreases, making option 3 correct. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It becomes more negative as objects approach. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: Halliday & Resnick, Fundamentals of Physics, 11th ed., Chapter 13: Gravitation.
A. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Angular momentum is correct because its dimensions and unit match the physical quantity asked.
Ref: NCERT Class 11 Physics > Chapter 2: Units and Measurements > Topic: SI Units and Dimensional Formulae
Work, energy, and torque share the same dimensional formula \[ML2T−2\], while pressure is \[ML−1T−2\]. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Pressure is correct because its dimensions and unit match the physical quantity asked.
Ref: NCERT Class 11 Physics > Chapter 2: Units and Measurements > Topic: SI Units and Dimensional Formulae
Derived units are formed by combining base units. Base units are fundamental and independent. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Kilogram (kg) is correct because its dimensions and unit match the physical quantity asked.
Ref: NCERT Class 11 Physics > Chapter 2: Units and Measurements > Topic: SI Units and Dimensional Formulae
Reynolds number is a pure ratio and has no physical dimensions. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Reynolds number is correct because its dimensions and unit match the physical quantity asked.
Ref: NCERT Class 11 Physics > Chapter 2: Units and Measurements > Topic: SI Units and Dimensional Formulae
Mutations do not always result in beneficial changes; they can also be harmful or neutral.
Ref: NCERT Class 12 Biology Chapter 6: Evolution Darwinism Lamarckism and Modern Synthetic Theory
Lamarck's theory of use and disuse is not widely accepted; Darwin's theory of natural selection is the accepted mechanism of evolution.
Ref: NCERT Class 12 Biology Chapter 6: Evolution Darwinism Lamarckism and Modern Synthetic Theory
Oxytocin, secreted by the posterior pituitary, stimulates uterine contractions and helps in milk ejection during breastfeeding.
Ref: NCERT Class 11 Biology Chapter 19: Chemical Coordination and Integration Endocrine System and Hypothalamus Pituitary Axis
Tracheophytes including pteridophytes, gymnosperms and angiosperms all contain lignified xylem tracheary elements with bordered pits facilitating efficient long-distance water transport under negative pressure and structural support enabling tall upright growth independent of turgor. Nonvascular plants lack true lignified xylem and phloem, instead possess hydroids lacking lignin and leptoids for conduction plus external capillary action, limiting size to few centimeters. Bryophytes constitute sole recognized extant group occupying nonvascular grade. Classifying bryophytes as nonvascular aligns with morphology, life cycle dominance, and molecular phylogeny distinguishing basal land plants.
Ref: Vanderpoorten & Goffinet Bryophyte Biology 2nd ed.; Campbell Ch 29: Nonvascular
