Exams › JEE Main › Physics

Two small bar magnets P and Q are placed far apart with their centres lying on the X-axis. The magnetic axis of P is along the X-axis, while that of Q is along the Y-axis. At point R, which is exactly midway between the two centres, let B denote the magnitude of the magnetic induction produced by Q alone. The magnitude of the resultant magnetic induction at R due to both magnets is

1. 3B
2. √5B
3. (√5/2) B
4. B

Correct answer: √5B

Solution

The resultant magnetic induction at point R is found by vectorially adding the magnetic fields from both magnets. Since magnet P's field is along the X-axis and magnet Q's field is along the Y-axis, the resultant forms a right triangle, leading to the calculation of the resultant magnitude as √(B² + B²) = √5B.

Related JEE Main Physics questions

• The SI unit Weber is used for measuring which of the following quantities?
• Two identical magnetic dipoles, each having magnetic moment 1.0 A·m², are kept 2 m apart with their axes mutually perpendicular. The magnetic field at the midpoint between them is
• A material has relative permittivity εr and relative permeability μr. For a diamagnetic substance, which pair of values is physically permissible?
• A bar magnet freely suspended in the horizontal component of Earth’s magnetic field H has a time period of 4 s. If a second magnet is placed nearby and the time period becomes 2 s, then the magnetic field produced by the second magnet is:
• Which magnetic properties should the core material possess to be suitable for an electromagnet?
• A bar magnet has a length much greater than its width and thickness. In a vibration magnetometer, its oscillation period is 2 s. The magnet is then divided lengthwise into three equal pieces, and the three pieces are stacked together so that like poles are in contact. What is the oscillation period of this arrangement?

⚔️ Practice JEE Main Physics free + battle 1v1 →