Moving Charges ...

Two identical particles having the same mass m and charges +q and - q separated by a distance d enter in a uniform magnetic field B directed perpendicular to paper inwards with speed $$v _ { 1 } \text { and } v _ { 2 }$$ as shown in figure. The particles will not collide if

Proton and $$\alpha$$ particle enters in stable uniform magnetic field with same kinetic energy. If the radius of circular path are $$r_{p}$$ and $$r_{a}$$, then,

A particle with charge q and , mass m starts its motion from origin with a velocity $$\overrightarrow v  = a\widehat i$$. A uniform magnetic field $$\overrightarrow B  = \dfrac{b}{4}\widehat i + \dfrac{{\sqrt 3 b}}{4}\widehat j$$ exists everywhere in space. The component of the velocity vector in y-direction when the value of z-coordination becomes maximum is 

Several $$\alpha-$$ particle of different speeds enter a uniform magnetic field confined into a cylindrical region. if all the $$\alpha-$$ particles enter the field radially, what can say about time intervals spent by them in the magnetic field?

Two point charges $$A$$ and $$B$$ of same charge having magnitude of momentum $$p_1$$ and $$p_2$$ respectively and having same charge are moving in a plane containing uniform magnetic field perpendicular to the plane. Then (Trajectories as shown in figure)  

Current $$I$$ flowing along edges of face of a cube as shown in the figure $$i$$, produces magnetic field $$\vec{B}=B_{o}\hat{j}$$ at the centre of the cube. Consider another identical cube. where the current. $$I$$ flows along the path shown in the figure $$II$$. How much magnetic field exist at the centre of the second cube?

A $$\gamma -$$ray photon is passing near a nucleus, and breaks into an electron and positron. The region contains a uniform magnetic field $$B$$ perpendicular to the plane of motion. The time after which they again converted into $$\gamma -$$ray is : 
[The force of electrostatic interaction and gravitational interaction may be neglected]

A particle of mass $$m$$, carrying in a uniform magnetic field directed along $$x-$$axis. At the instant $$t=0$$ it is given a velocity $$v_0$$ at an angle $$\theta$$ with the $$y-$$axis, in the $$x-y$$ plane. The coordinates of the particle after one revolution will be :

A long straight wire and a circular loop carrying currents $$I_1$$ and $$I_2$$ respectively are in the same plane as shown in figure. If the magnetic field at the centre of the loop is zero, then :

An electron accelerated through a potential difference $$V$$ enters into a uniform transverse magnetic field and experiences a force $$F$$. If the acceleration potential is increased to $$2V$$, the electron in the same magnetic field will experience a force :