1
IIT-JEE 2012 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2

Consider the motion of a positive point charge in a region, there are simultaneous uniform electric and magnetic fields $$\overrightarrow E = {E_0}\widehat j$$ and $$\overrightarrow B = {B_0}\widehat j$$. At time t = 0, this charge has velocity $$\overrightarrow v$$ in the xy-plane, making an angle $$\theta$$ with the x-axis. Which of the following option(s) is(are) correct for time t > 0 ?

A
If $$\theta$$ = 0$$^\circ$$, the charge moves in a circular path in the xy-plane.
B
If $$\theta$$ = 0$$^\circ$$, the charge undergoes helical motion with constant pitch along the y-axis.
C
If $$\theta$$ = 10$$^\circ$$, the charge undergoes helical motion with its pitch increasing with time, along the y-axis.
D
If $$\theta$$ = 90$$^\circ$$, the charge undergoes linear but accelerated motion along the y-axis.
2
IIT-JEE 2011 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2

An electron and a proton are moving on straight parallel paths with same velocity. They enter a semi-infinite region of uniform magnetic field perpendicular to the velocity. Which of the following statement(s) is/are true?

A
They will never come out of the magnetic field region.
B
They will come out travelling along parallel paths.
C
They will come out at the same time.
D
They will come out at different times.
3
IIT-JEE 2008 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2

A particle of mass m and charge q, moving with velocity v enters Region II normal to the boundary as shown in the figure. Region II has a uniform magnetic field B perpendicular to the plane of the paper. The length of the Region II is $$l$$. Choose the correct choice (s).

A
The particle enters Region III only if its velocity $$v > {{qlB} \over m}$$
B
The particle enters Region III only if its velocity $$v < {{qlB} \over m}$$
C
Path length of the particle in Region II is maximum when velocity $$v = {{qlB} \over m}$$
D
Time spent in Region II is same for any velocity v as long as the particle returns to Region I
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