JEE Mains · Physics · STD 12 - 5. Magnetism and matter
The current required to be passed through a solenoid of \(15\,cm\) length and 60 turns in order to demagnetise a bar magnet of magnetic intensity \(2.4 \times 10^3\,Am ^{-1}\) is \(.........A\).
- A \(3\)
- B \(2\)
- C \(8\)
- D \(6\)
Answer & Solution
Correct Answer
(D) \(6\)
Step-by-step Solution
Detailed explanation
\(I = H\) Given, \(I =2.4 \times 10^3\,A / m\) \(2.4 \times 10^3= H = ni\) \(n =\frac{ N }{\ell}\) \(2.4 \times 10^3=\frac{60}{15 \times 10^{-2}} i\) \(i =\frac{2.4 \times 15 \times 10}{60}=\frac{36}{6}=6\,A\)
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
- A particle is moving with constant acceleration \('a'.\) Following graph shows \(v^{2}\) versus \(x\) (displacement) plot. The acceleration of the particle is \(......{m} / {s}^{2}\)
JEE Mains 2021 Hard - Assuming the nitrogen molecule is moving with \(r.m.s.\) velocity at \(400\, K\), the de\(-\)Broglie wavelength of nitrogen molecule is close to\(......\mathring {A}\) (Given : nitrogen molecule weight : \(4.64 \times 10^{-26}\, kg ,\) Boltzman constant : \(1.38 \times 10^{-23}\, J / K ,\) Planck constant : \(\left.6.63 \times 10^{-34}\, J . s \right)\)JEE Mains 2020 Hard
- An electron of mass \(m _{ e }\) and a proton of mass \(m _{ p }=1836 m _{ e }\) are moving with the same speed. The ratio of their de Broglie wavelength \(\frac{\lambda_{\text {electron }}}{\lambda_{\text {proton }}}\) will be ....... .JEE Mains 2021 Medium
- A hydrogen atom in ground state is given an energy of \(10.2 \mathrm{eV}\). How many spectral lines will be emitted due to transition of electrons?JEE Mains 2024 Medium
- Two charges \(7 \mu C\) and \(-2 \mu C\) are placed at \((-9,0,0) cm\) and \((9,0,0) cm\) respectively in an external field \(E=\frac{ A }{ r ^2} \hat{ r }\), where \(A=9 \times 10^5 N / C . m ^2\).
Considering the potential at infinity is 0 , the electrostatic energy of the configuration is ___________ J .JEE Mains 2026 Medium - A capacitor of capacitance \(100\ \mu \mathrm{F}\) is charged to a potential of \(12 \mathrm{~V}\) and connected to a \(6.4 \ \mathrm{mH}\) inductor to produce oscillations. The maximum current in the circuit would be :JEE Mains 2024 Hard
More PYQs from JEE Mains
- Let \(\vec{a} = 2\hat{i} + 3\hat{j} + 3\hat{k}\) and \(\vec{b} = 6\hat{i} + 3\hat{j} + 3\hat{k}\). Then the square of the area of the triangle with adjacent sides determined by the vectors \((2\vec{a} + 3\vec{b})\) and \((\vec{a} - \vec{b})\) is :JEE Mains 2026 Medium
- Let \(\overrightarrow{ a }=\hat{ i }+2 \hat{ j }-\hat{ k }, \overrightarrow{ b }=\hat{ i }-\hat{ j }\) and \(\overrightarrow{ c }=\hat{ i }-\hat{ j }-\hat{ k }\) be three given vectors. If \(\overrightarrow{ r }\) is a vector such that \(\overrightarrow{ r } \times \overrightarrow{ a }=\overrightarrow{ c } \times \overrightarrow{ a }\) and \(\overrightarrow{ r } \cdot \overrightarrow{ b }=0,\) then \(\overrightarrow{ r } \cdot \overrightarrow{ a } \quad\) is equal to ...........JEE Mains 2021 Medium
- The aperture diameter of a telescope is \(5\; \mathrm{m} .\) The separation between the moon and the earth is \(4 \times 10^{5} \;\mathrm{km} .\) With light of wavelength of \(5500\;\mathring A\), the minimum separation between objects on the surface of moon, so that they are just resolved, is close to......\(m\)JEE Mains 2020 Medium
- When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :JEE Mains 2024 Hard
- A alternating current at any instant is given by \(i=\left[6+\sqrt{56} \sin \left(100 \pi t+\frac{\pi}{3}\right)\right] A\). The rms value of the current is _________ A.JEE Mains 2024 Hard
- Light source having wavelength \(331\) nm is used to generate photo-electrons whose stopping potential is \(0.2\) V. The work function of the used metal in the experiment is \(\alpha \times 10^{-19}\) J. The value of \(\alpha\) is _____.
(\(h = 6.62 \times 10^{-34}\) J s, \(e = 1.6 \times 10^{-19}\) C and \(c = 3 \times 10^8\) m/s)JEE Mains 2026 Medium