Magnetic Effects Of Current Question 270
Question: A uniform magnetic field B is acting from south to north and is of magnitude 1.5 $ Wb/m^{2} $ . If a proton having mass $ =1.7\times {{10}^{-27}},kg $ and charge $ =1.6\times {{10}^{-19}},C $ moves in this field vertically downwards with energy 5 MeV, then the force acting on it will be [Pb. PMT 2002]
Options:
A) $ 7.4\times 10^{12},N $
B) $ 7.4\times {{10}^{-12}},N $
C) $ 7.4\times 10^{19},N $
D) $ 7.4\times {{10}^{-19}},N $
Show Answer
Answer:
Correct Answer: B
Solution:
$ F=qvB $ and $ K=\frac{1}{2}mv^{2} $
Þ $ F=qB\sqrt{\frac{2k}{m}} $ $ =1.6\times {{10}^{-19}}\times 1.5\sqrt{\frac{2\times 5\times 10^{6}\times 1.6\times {{10}^{-19}}}{1.7\times {{10}^{-27}}}} $ $ =7.344\times {{10}^{-12}},N $
BETA
