In a region of space, a uniform magnetic field B exists in the x-direction. An electron is fired from the origin with its initial velocity u making an angle α with the y direction in the y-z plane. In the subsequent motion of the electron,

Question

In a region of space, a uniform magnetic field B exists in the x-direction. An electron is fired from the origin with its initial velocity u making an angle α with the y direction in the y-z plane. In the subsequent motion of the electron, (A) y-coordinate of the electron will never be negative (B) z-coordinate of the electron will never be negative (C) x-coordinate of the electron will never be negative (D) trajectory of the electron would be helical

Tardigrade Admin · Accepted Answer

We can see from trajectory that both y - and z-coordinates can become negative. This trajectory lies in y-z plane. So, x-coordinate is always zero.

Q. In a region of space, a uniform magnetic field $B$ exists in the $x$ -direction. An electron is fired from the origin with its initial velocity $u$ making an angle $α$ with the $y$ direction in the $y - z$ plane. In the subsequent motion of the electron,

$y$ -coordinate of the electron will never be negative

$z$ -coordinate of the electron will never be negative

$x$ -coordinate of the electron will never be negative

trajectory of the electron would be helical

We can see from trajectory that both $y$ - and $z$ -coordinates can become negative. This trajectory lies in $y - z$ plane. So, $x$ -coordinate is always zero.

Q. In a region of space, a uniform magnetic field B exists in the x-direction. An electron is fired from the origin with its initial velocity u making an angle α with the y direction in the y−z plane. In the subsequent motion of the electron,

y-coordinate of the electron will never be negative

z-coordinate of the electron will never be negative

x-coordinate of the electron will never be negative