Velocity selector
Magnetic field and forces · Physics
DC circuit
Interactive 3DElectrons drift around the loop — raise the voltage and watch the current obey Ohm's law.
Controls
Drag the sliders or type a value — the simulation updates live.
Study notes
Problem: A velocity selector has an electric field magnitude of 100 V/m and a magnetic field magnitude of 0.5 T. What is the velocity of a charged particle that passes through undeflected? Steps: 1. Identify the condition for undeflected motion: The electric force (Fe) must equal the magnetic force (Fb). Therefore, qE = qvB. 2. Cancel the charge (q) from both sides since it is common to both forces. This gives E = vB. 3. Rearrange the formula to solve for velocity (v): v = E / B. 4. Substitute the given values: E = 100 V/m and B = 0.5 T. 5. Calculate: v = 100 / 0.5 = 200 m/s. Answer: The velocity of the particle is 200 m/s.