JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
A current of \(30\) A each flows in opposite directions in two conducting wires, placed parallel to each other at a distance of \(8\) cm. The magnetic field at the mid point between the two wires is __________ \(\mu\)T. \(\left(\dfrac{\mu_0}{4\pi} = 10^{-7}\text{ N/A}^2\right)\)
- A \(30\)
- B \(300\)
- C \(150\)
- D \(0.0\)
Answer & Solution
Correct Answer
(B) \(300\)
Step-by-step Solution
Detailed explanation
Let the distance between the wires be \(d = 8\text{ cm}\). The distance of the midpoint from each wire is \(r = \dfrac{d}{2} = 4\text{ cm} = 0.04\text{ m}\). The current in each wire is \(I = 30\text{ A}\). Since the currents flow in opposite directions, the magnetic fields…
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 stationary horizontal disc is free to rotate about its axis. When a torque is applied on it, its kinetic energy as a function of \(\theta ,\) where \(\theta \) is the angle by which it has rotated, is given as \(k\theta ^2.\) If its moment of inertia is \(I\) then the angular acceleration of the disc isJEE Mains 2019 Hard
- The general displacement of a simple harmonic oscillator is \(x = A \sin \omega t\). Let \(T\) be its time period. The slope of its potential energy (U) - time (t) curve will be maximum when \(t=\frac{T}{\beta}\). The value of \(\beta\) is \(.........\)JEE Mains 2023 Hard
- A water heater of power \(2000\,W\) is used to heat water. The specific heat capacity of water is \(4200\,J\,kg ^{-1}\, K ^{-1}\). The efficiency of heater is \(70 \%\). Time required to heat \(2\,kg\) of water from \(10^{\circ}\,C\) to \(60^{\circ}\,C\) is \(..........s\). (Assume that the specific heat capacity of water remains constant over the temperature range of the water).JEE Mains 2023 Medium
- Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The binding energy per nucleon is found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170.
Reason (R): Nuclear force is long range.
In the light of the above statements, choose the correct answer from the options given below :JEE Mains 2025 Easy - Three capacitors of capacitances \(25 \mu \mathrm{F}, 30 \mu \mathrm{F}\) and \(45 \mu \mathrm{F}\) are connected in parallel to a supply of \(100\) \(V\). Energy stored in the above combination is \(\mathrm{E}\). When these capacitors are connected in series to the same supply, the stored energy is \(\frac{9}{\mathrm{x}} \mathrm{E}\). The value of \(x\) is _______.JEE Mains 2024 Hard
- The temperature of \(3.00\, {mol}\) of an ideal diatomic gas is increased by \(40.0^{\circ} {C}\) without changing the pressure of the gas. The molecules in the gas rotate but do not oscillate. If the ratio of change in internal energy of the gas to the amount of workdone by the gas is \(\frac{{x}}{10} .\) Then the value of \({x}\) (round off to the nearest integer) is ..... . \(\left(\right.\) Given \(\left.{R}=8.31\, {J} {mol}^{-1} {K}^{-1}\right)\)JEE Mains 2021 Medium
More PYQs from JEE Mains
- A circular loop of radius 7 cm is placed in uniform magnetic field of 0.2 T directed perpendicular to plane of loop. The loop is converted into a square loop in 0.5 s . The EMF induced in the loop is ___________ mV.JEE Mains 2026 Medium
- A compound microscope consists of an objective lens of focal length \(1 \,cm\) and an eye piece of focal length \(5 \,cm\) with a separation of \(10 \,cm\) The distance between an object and the objective lens, at which the strain on the eye is minimum is \(\frac{ n }{40}\, cm .\) The value of \(n\) is\(....\)JEE Mains 2020 Medium
- The number of elements in the set
\( S=\{x:x\in[0,100] \text{ and } \int_{0}^{x}t^{2}sin(x-t)dt=x^{2}\} \) is:JEE Mains 2026 Easy - Let \(y=y(x)\) be the solution of the differential equation, \(x y^{\prime}-y=x^{2}(x \cos x+\sin x), x>0\) If \(y (\pi)=\pi,\) then \(y ^{\prime \prime}\left(\frac{\pi}{2}\right)+ y \left(\frac{\pi}{2}\right)\) is equal toJEE Mains 2020 Hard
- The recoil speed of a hydrogen atom after it emits a photon in going from \(n =5\) state to \(n =1\) state will be ..... \(m/s\)JEE Mains 2021 Hard
- In a test experiment on a model aeroplane in wind tunnel, the flow speeds on the upper and lower surfaces of the wings are \(70 \mathrm{~ms}^{-1}\) and \(65 \mathrm{~ms}^{-1}\) respectively. If the wing area is \(2 \mathrm{~m}^2\) the lift of the wing is _______ \(\mathrm{N}\). (Given density of air \(=1.2 \mathrm{~kg} \mathrm{~m}^{-3}\) )JEE Mains 2024 Hard