Consider the motion of a positive point charge in a region where are simultaneous uniform electric and magnetic field $\to E = E_{0}^j$ and $\to B = B_{0}^j$ . At time $t = 0$ , this charge has velocity $\to v$ in the x-y plane, making an angle $θ$ with the x-axis. Which of the following option(s) is (are) correct for time $t > 0$ ?
If $θ = 0^{o}$ , the charge undergoes helical motion with constant pitch along the y-axis
If $θ = 0^{o}$ , the charge moves in a circular path in the x-z plane
If $θ = 90^{o}$ , the charge undergoes linear but accelerated motion along the y-axis
If $θ = 10^{o}$ , the charge undergoes helical motion with pitch increasing with time, along the y-axis

Question

Consider the motion of a positive point charge in a region where are simultaneous uniform electric and magnetic field $\to E = E_{0}^j$ and $\to B = B_{0}^j$ . At time $t = 0$ , this charge has velocity $\to v$ in the x-y plane, making an angle $θ$ with the x-axis. Which of the following option(s) is (are) correct for time $t > 0$ ?
If $θ = 0^{o}$ , the charge undergoes helical motion with constant pitch along the y-axis
If $θ = 0^{o}$ , the charge moves in a circular path in the x-z plane
If $θ = 90^{o}$ , the charge undergoes linear but accelerated motion along the y-axis
If $θ = 10^{o}$ , the charge undergoes helical motion with pitch increasing with time, along the y-axis

Toppr Admin · Accepted Answer

If -x3B8-0o then due to magnetic force path is circular but due to force qE0-x2191-q will have accelerated motion along y-axis- So combined path of q will be a helical path with variable pitch so -a- and -b- are wrong-If -x3B8-10o- then due to vcos-x3B8- path is circular and due to qE0 and vsin-x3B8- q has accelerated motion along y-axis so combined path is a helical path with variable pitch -C- is correct-If -x3B8-90o then FB-0 and due to qE0 motion is accelerated along y-axis -D-