Question

A charge is projected with a velocity of ${10}^{5}m/s$. In a perpendicular magnetic field. Find the magnetic of a transverse electric field if if moves undeflected. $\left(B=4\ast {10}^{-5}T\right)$

• A. 4 N/C
• B. $4\times {10}^{-2}N/C$
• C. $24\times {10}^{-2}N/C$
• D. not possible

Answer 1

Answer: (A)

4 N/C

For undefelcted path:Magnetic force =electric field

$⟹F_B=F_E\to BqV\sin \theta =qE$

Where $B=$magnetic field, $q=$ charge,$V=$velocity, $E$=electric field

$⟹BV\sin 90=E$

$⟹4\times {10}^{-5}\times {10}^5\times 1=E$

$E=4N/C$