NEET · Physics · STD 12 - 3. current electricity
A copper wire of length \(10\,m\) and radius \(\left(10^{-2} / \sqrt{\pi}\right) m\) has electrical resistance of \(10 \,\Omega\). The current density in the wire for an electric field strength of \(10( V / m )\) is :
- A \(10^{6} A / m ^{2}\)
- B \(10^{-5} A / m ^{2}\)
- C \(10^{5} A / m ^{2}\)
- D \(10^{4} A / m ^{2}\)
Answer & Solution
Correct Answer
(C) \(10^{5} A / m ^{2}\)
Step-by-step Solution
Detailed explanation
Radius of wire \(=\frac{10^{-2}}{\sqrt{\pi}}\) Cross sectional area \(A =\pi r ^{2}=10^{-4} m ^{2}\) \(j =\frac{ i }{ A }=\left(\frac{ V }{ R }\right) \cdot \frac{1}{ A }=\frac{ E \ell}{ RA } \quad R =\frac{\rho \ell}{ A }\) \(j =\frac{10 \times 10}{10 \times 10^{-4}}=10^{5} A / m ^{2}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- In a concave lens, a ray of light emanating from the object parallel to the principal axis of the lens, after refraction :NEET 2026 Medium
- The ratio of the magnitude of the magnetic field and electric field intensity of a plane electromagnetic wave in free space of permeability \(\mu_0\) and permittivity \(\varepsilon_0\) is (Given that \(c\) - velocity of light in free space)NEET 2022 Easy
- A radioactive nucleus \({ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X}\) undergoes spontaneous decay in the sequence \({ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X} \rightarrow {}_{\mathrm{Z}-1}{\mathrm{B}} \rightarrow {}_{\mathrm{Z}-3 }\mathrm{C} \rightarrow {}_{\mathrm{Z}-2} \mathrm{D}\), where \(\mathrm{Z}\) is the atomic number of element \(X.\) The possible decay particles in the sequence are :NEET 2021 Medium
- A liquid does not wet the solid surface if angle of contact isNEET 2020 Easy
- A particle moves from a point \(\left( { - 2\hat i + 5\hat j} \right)\) to \(\left( {4\hat j + 3\hat k} \right)\) when a force of \(\left( {4\hat i + 3\hat j} \right)\) is applied. How much work has been done by the force ?......\(J\)NEET 2016 Easy
- In a certain reglon of space with volume \(0.2\, m ^{3}\) the electric potential is found to be \(5\, V\) throughout. The magnitude of electric field in this region is ______ \(N/C\)NEET 2020 Easy
More PYQs from NEET
- Out of \(‘X ’\) pairs of ribs in humans only \(‘Y' \) pairs are true ribs. Select the option that correctly represents values of \(X\) and \(Y\) and provides their explanation.NEET 2017 Medium
- Match List I with List II :
List I List II A. Decomposition I. Accumulation of dark coloured amorphous colloidal substance B. Detritus II. Release of inorganic nutrients by the activity of microbes in soil C. Mineralisation III. Breaking down of complex organic matter into inorganic substances D. Humification IV. Dead remains of plants and animals including faecal matter NEET 2026 Easy - Exploration of molecular, genetic and species level diversity for novel products of economic importance is known asNEET 2019 Medium
- Which of the following types of plastid does not contain stored food material?NEET 2013 Medium
- Identify the correct statements:
A. The molality of 2.5 g of ethanoic acid (Molar mass : \(60 g mol ^{-1}\)) in 75 g of benzene solution is 0.556 m.
B. The molarity of a solution containing 5 g of NaOH (molar mass: \(40 g mol ^{-1}\)) in 450 mL of solution is 0.278 M at 298 K.
C. Aquatic species are more comfortable in cold water.
D. The solubility of gas increases with decrease in pressure.
E . For a binary mixture of A and B , the number of moles of A and B are \(n_A\) and \(n_B\) respectively. The mole fraction of B will be \(x_B=\frac{n_A}{n_A+n_B}\).
Choose the correct answer from the options given below :NEET 2026 Hard - A disc of radius \(2\; \mathrm{m}\) and mass \(100\; \mathrm{kg}\) rolls on a horizontal floor. Its centre of mass has speed of \(20\; \mathrm{cm} / \mathrm{s} .\) How much work is needed to stop it?NEET 2019 Medium