Magnetic Effects Of Current Question 340
Question: An electron (mass = 9´ 10?31kg. Charge = 1.6 ´ 10?19C) whose kinetic energy is 7.2 ´ 10?18 joule is moving in a circular orbit in a magnetic field of 9 ´ 10?5 weber/m2. The radius of the orbit is [MP PMT 2002]
Options:
A) 1.25 cm
B) 2.5 cm
C) 12.5 cm
D) 25.0 cm
Show Answer
Answer:
Correct Answer: D
Solution:
$ r=\frac{\sqrt{2mE}}{qB}=\frac{\sqrt{2\times 9\times {{10}^{-31}}\times 7.2\times {{10}^{-18}}}}{1.6\times {{10}^{-19}}\times 9\times {{10}^{-5}}} $ = 0.25 m = 25 cm
BETA
