Magnetic Effects Of Current Question 253
Question: A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $ \overrightarrow{E} $ and $ \overrightarrow{B} $ represent the electric and magnetic fields respectively, then this region of space may have [IIT-JEE 1985; AMU 1995; AFMC 2001; Roorkee 2000; AMU (Med.) 2000]
Options:
A) $ E=0,,B=0 $
B) $ E=0,,B\ne 0 $
C) $ E\ne 0,,B=0 $
D) $ E\ne 0,,B\ne 0 $
Show Answer
Answer:
Correct Answer: A
Solution:
Here the proton has no acceleration so $ E=B=0. $ When $ E=0 $ but $ B\ne 0, $ and parallel to the motion of proton, there will be no force acting. When $ E\ne 0 $ and $ B\ne 0 $ and E, B and motion of proton $ ( v ) $ are mutually perpendicular, there may be no net force. Forces due to E and B do not necessarily cancel each other.
BETA
