Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Moving Charges and Magnetism

Question:

A magnetic field of 5×10−4T just balances a perpendicular electric field of 15 kV/m in their effect on an electron beam passing through the two fields in a direction perpendicular to both of them. What is the speed of the electrons?

Options:
75 m/s

3×104 m/s

3×107 m/s

3.5 ×103 m/s
Correct Answer:

3×107 m/s

Explanation:

v = \(\frac{E}{B}\) = \(\frac{15 x 10^{3}}{5 x 10^{-4}}\)

   = 3×107 m/s