Join WhatsApp Icon JEE WhatsApp Group
Question 32

If $$\epsilon$$, E and t represent the free space permittivity, electric field and time respectively, then the unit of $$ \frac{\epsilon E}{t}$$ will be :

The electric displacement vector $$\mathbf{D}$$ is related to the electric field $$\mathbf{E}$$ by the constitutive relation $$\mathbf{D} = \epsilon \mathbf{E}$$.

By definition, the surface integral $$\iint \mathbf{D}\,\cdot d\mathbf{S}$$ equals the free charge $$q$$ enclosed. Hence the unit of $$\mathbf{D}$$ (and therefore of $$\epsilon E$$) must be the unit of charge per unit area, that is $$\text{coulomb per square metre}$$, written as $$C/m^{2}$$.

We now divide by time $$t$$, whose SI unit is the second, $$s$$:

$$\frac{\epsilon E}{t} \; \text{has unit} \; \frac{C/m^{2}}{s} = \frac{C}{m^{2}\,s}.$$

Since $$1\,\text{ampere} = 1\,\text{coulomb}\,\text{s}^{-1}$$, we replace $$C/s$$ by $$A$$:

$$\frac{C}{m^{2}\,s} = \frac{A}{m^{2}}.$$

Thus, the unit of $$\dfrac{\epsilon E}{t}$$ is $$A/m^{2}$$.

Correct option: Option B.

Get AI Help

Create a FREE account and get:

  • Free JEE Mains Previous Papers PDF
  • Take JEE Mains paper tests

JEE Quant Questions | JEE Quantitative Ability

JEE DILR Questions | LRDI Questions For JEE

JEE Verbal Ability Questions | VARC Questions For JEE

Free JEE Topicwise Questions

JEE Rotational MotionJEE Units & MeasurementsJEE Atomic StructureJEE GravitationJEE Periodic Table & PeriodicityJEE StatisticsJEE Inverse Trigonometric FunctionsJEE Magnetism & Magnetic MaterialsJEE Sequences & SeriesJEE MatricesJEE Alternating CurrentsJEE Carboxylic AcidsJEE Permutations & CombinationsJEE Work, Energy & PowerJEE Electromagnetic InductionJEE Electronic DevicesJEE d and f-Block ElementsJEE Chemical KineticsJEE Heat TransferJEE Three Dimensional GeometryJEE Magnetic Effects of CurrentJEE Hydrocarbons - AromaticJEE Electromagnetic WavesJEE Aldehydes & KetonesJEE Hydrocarbons - AlkanesJEE Applications of DerivativesJEE EquilibriumJEE Indefinite IntegrationJEE Chemical ThermodynamicsJEE ElectrochemistryJEE ProbabilityJEE BiomoleculesJEE Continuity & DifferentiabilityJEE Kinetic Theory of GasesJEE Vector AlgebraJEE Hydrocarbons - AlkynesJEE Differential EquationsJEE Current & ResistanceJEE Straight LinesJEE WavesJEE Redox ReactionsJEE Hydrocarbons - AlkenesJEE DeterminantsJEE SolutionsJEE Ray OpticsJEE Dual Nature of Matter & RadiationJEE Chemical Bonding & Molecular StructureJEE Complex NumbersJEE Sets, Relations & FunctionsJEE Electric Charges & FieldsJEE Laws of MotionJEE Fluid MechanicsJEE Basic Concepts in ChemistryJEE Trigonometric FunctionsJEE LimitsJEE Laws of ThermodynamicsJEE Kinematics - 2D MotionJEE p-Block Elements (Groups 13-18)JEE Simple Harmonic MotionJEE Electric Potential & CapacitanceJEE Coordination CompoundsJEE JEE 2D GeometryJEE CirclesJEE Definite IntegrationJEE EMF & Circuit AnalysisJEE Surface TensionJEE Atoms & NucleiJEE Laboratory Experiments - XIJEE Number SystemJEE Basic Principles of Organic ChemistryJEE Wave OpticsJEE Quadratic EquationsJEE Alcohols, Phenols & EthersJEE Organic Compounds with HalogensJEE DifferentiationJEE Conic SectionsJEE Nitrogen-Containing CompoundsJEE ElasticityJEE Practical Organic ChemistryJEE Kinematics - 1D MotionJEE Purification & CharacterisationJEE Binomial Theorem
Ask AI