Question

In a cathode ray tube electric and magnetic fields are simultaneously applied mutually at right angles to each other and also at right angles to the direction of motion of the cathode rays, such that the cathode ray beam is un-deflected. If the electric intensity is 500 $Vc{m}^{-1}$ and the magnetic induction is 0.01 tesla, the velocity of the cathode ray particles is

• A. 50 ×10⁶ ms^-1
• B. 5 ×10⁵ ms^-1
• C. 5 ×10⁷ ms^-1
• D. 5 ×10⁴ ms^-1

Answer 1

The correct option is D

5 ×10⁴ ms^-1

Velocity of cathode ray particle, v = $\frac{E}{B}$