COMEDK · Physics · 21. Magnetic Effects of Current
A straight wire of mass 250 g and length 2.5 m carries a current of 4 A . It can be suspended in mid air by a uniform horizontal magnetic field of magnitude:
- A 2.245 T
- B 0.625 T
- C 0.145 T
- D 0.245 T
Answer & Solution
Correct Answer
(D) 0.245 T
Step-by-step Solution
Detailed explanation
The wire is suspended in mid-air, which implies that the magnetic force acting on the wire must balance the gravitational force acting on it. The gravitational force \(F_g\) acting on the wire is given by \(F_g = mg\), where \(m = 250 \text{ g} = 0.25 \text{ kg}\) and…
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 circular coil of area \(2 \sqrt{2} \mathrm{~cm}^2\) and resistance \(2 \boldsymbol{\Omega}\) is arranged vertically in the east -west direction. A uniform magnetic field 0.2 T is set up across the plane in the north to east direction. Now the magnetic field is removed at a steady rate in 0.4 s What is the current developed in the coil?COMEDK 2025 Medium
- A neutral water molecule, modeled as an electric dipole with an effective charge equal to one elementary charge (\(e = 1.6 \times 10^{-19} \text{ C}\)), is placed in an electric field \(E = 2.5 \times 10^4 \text{ NC}^{-1}\). The work done to rotate it by \(180^\circ\) from its stable equilibrium position is \(5 \times 10^{-25} \text{ J}\). Find the approximate separation of the centre of charges.COMEDK 2024 Medium
- The ratio of the magnetic fields at the centre of a circular coil carrying current to that at a point whose distance is half of the radius of the coil isCOMEDK 2012 Medium
- A ray of light incident on one face of an equilateral prism at \(60^{\circ}\) enters and leaves the prism symmetrically. Refractive index of the prism material isCOMEDK 2016 Medium
- Column - I lists the waves of the electromagnetic spectrum. Column - II gives approximate frequency range of these waves. Match Column - I and Column - II and choose the correct match from the given choices.
No. Column I No. Column II A Radiowaves P \(10^{18}\) to \(10^{20}\) Hz B Microwaves Q \(10^{11}\) to \(5 \times 10^{14}\) Hz C Infrared R \(10^{4}\) to \(10^{8}\) Hz D X-rays S \(10^{9}\) to \(10^{12}\) Hz COMEDK 2024 Easy - Two amplifiers are connected one after the other in series (cascaded). The first amplifier has a voltage gain of 10 and the second has a voltage gain of 20 . If the input signal is \(0.01 \mathrm{~V}\), what is the output AC signal?COMEDK 2014 Easy
More PYQs from COMEDK
- Match the details given in Column I with those given in Column II
S.No. Column I S.No. Column II A For complex reactions order is determined by P Rate of reaction. B For Zero order reaction unit of k is same as that of Q Slope \(= k/2.303\) C Mathematical expression which gives relationship between rate of reaction and concentrations of reactants is called R Slowest rate determining step. D For a first order reaction plot of \(\log[R_0]/[R]\) vs time gives S Rate law. COMEDK 2023 Medium - A crystalline solid has \(A^{-}\)ions at the corners and face centres, whereas \(B^{+}\)ions are at the body centre and edge centres of the unit cell. The simplest formula of the compound will beCOMEDK 2014 Easy
- A signature, written in carbon pencil weighs \(1 \mathrm{mg}\). What is the number of carbon atoms present in the signature?COMEDK 2013 Medium
- Which of the following has/have zero average value in a plane electromagnetic wave?COMEDK 2020 Easy
- A line \(L_1\) passes through the points \((h, k),(1,2)\) and \((-3,4)\). The points \((4,3)\) and \((h, k)\) lie on the line \(L_2\). Given \(L_1 \perp L_2\) then \((k-h)\) equals toCOMEDK 2025 Medium
- Arrange stability of the given carbon cation in decreasing order
COMEDK 2021 Medium