10 public questions tagged with this topic.
The metre, the SI unit of length, is defined by fixing the speed of light in vacuum as a constant value, expressed in metres per second, using the second as the time unit.
Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Relevant Physics topic covering fundamental principles,
Significant figures depend on least precise measurement. For 9.99 m (2 decimal places) minus 0.0099 m (4 decimal places), result 9.9801 m must be rounded to 2 decimal places as per subtraction rule in NCERT. So 9.98 m is correct, retaining 3 significant figures. Thus 3 follows significant figure rules.
Ref: NCERT Class 11 Physics > Chapter 2: Units and Measurements > Topic: SI Units and Dimensional Formulae
Dimensionless quantities like refractive index, strain, and angles have 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 Strain 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
Area is proportional to the square of length. So, if the unit of length doubles, the unit of area becomes four times larger. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Four times 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
Pressure and stress both share the same dimensional formula \[ML−1T−2\], but energy has \[ML2T−2\]. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Pressure and Energy 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
Pressure has the dimensional formula \[ML−1T−2\] while the others represent forms of energy or work. 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
Torque and work both have the dimensional formula \[ML2T−2\]. As per NCERT Class 11 Chapter 2, dimensional analysis checks correctness and SI units define base and derived quantities. This principle confirms that Work and Torque 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
2.54 (3 sig figs), 0.0821 (3 sig figs), 0.00123 (3 sig figs). Result ≈ 169.54; limited to 3 sig figs (170).
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Importance and Nature of Chemistry and Properties of Matter
0.0567 (3 sig figs), 298.15 (5 sig figs), 0.101 (3 sig figs). Result ≈ 167.34; limited to 3 sig figs (167).
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses
