Rankers Physics

Force Acting on Moving Charges: Practice Problem & Solution

A uniform electric field and uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron: (2011 Pre)
Will turn towards right of direction of motion
Speed will decrease
Speed will increase
Will turn towards left direction of motion

Solution Explained:

To solve this problem, we apply the core principles of Force Acting on Moving Charges. Understanding the underlying formula is key to arriving at the correct answer below:

The magnetic force is zero because velocity and magnetic field are parallel. The electric force acts opposite to the electron's motion since it is negatively charged, causing its speed to decrease.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. 25. If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by $\mu_d$, $\mu_p$ and $\mu_f$ respectively, then (2005)
2. A charge 'q' moves in a region where electric field and magnetic field both exist, then force on it is: (2002)
3. Assertion (A): Electric force between two like charged particles is repulsive but magnetic force between them could be attractive or repulsive or absent depending on the features of their motion. Reason (R): Magnetic field does not interact with static charges.  
4. A beam of cathode rays is subjected to crossed Electric (E) and Magnetic field (B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by (where V is the potential difference between cathode and anode): (2010 Pre)
5. A square current carrying loop is suspended in a uniform magnetic field acting in the plane of the loop. If the force on one arm of the loop is $vec{F}$, the net force on the remaining three arms of the loop is: (2010 Pre)