Understanding Velocity Selectors

What is the primary purpose of a velocity selector?

• To measure the charge of particles

• To change the direction of particles

• To filter particles based on their velocity

• To increase the speed of particles

Which two fields are used in a velocity selector to filter particles?

• Gravitational and electric fields

• Electric and magnetic fields

• Thermal and electric fields

• Magnetic and gravitational fields

What rule is used to determine the direction of the magnetic field in a velocity selector?

• Newton's rule

• Fleming's rule

• Right-hand rule

• Left-hand rule

In a velocity selector, what happens when the Lorentz force is greater than the electric force?

• Particles stop moving

• Particles are deflected downwards

• Particles are deflected upwards

• Particles travel straight through

What is the condition for particles to travel straight through a velocity selector?

• Electric force is greater than Lorentz force

• Lorentz force is greater than electric force

• Electric force equals Lorentz force

• No force acts on the particles

What is the formula for calculating the velocity of particles in a velocity selector?

• Velocity = Electric field strength + Magnetic field strength

• Velocity = Magnetic field strength / Electric field strength

• Velocity = Electric field strength / Magnetic field strength

• Velocity = Electric field strength x Magnetic field strength

If the velocity of particles is too low, what happens in a velocity selector?

• Particles are deflected upwards

• Particles stop moving

• Particles are deflected downwards

• Particles travel straight through

What must be true for particles to be deflected upwards in a velocity selector?

• No force acts on the particles

• Lorentz force is greater than electric force

• Electric force is greater than Lorentz force

• Electric force equals Lorentz force

In the example problem, what is the velocity of particles when the electric field strength is 2.0 x 10^3 V/m and the magnetic field strength is 50 mT?

• 30,000 m/s

• 50,000 m/s

• 40,000 m/s

• 20,000 m/s

In the second example problem, what is the magnetic field strength if the electric field strength is 1.25 x 10^7 V/m and the velocity is 5.0 x 10^7 m/s?

• 0.15 T

• 0.30 T

• 0.20 T

• 0.25 T