Question 5
[Maximum number: 1]
An electron moves with uniform circular motion in a region of magnetic field. Which diagram shows the acceleration a and velocity v of the electron at point P ?
A
B
C
D
IB Physics HL D.3 Motion in electromagnetic fields Question Bank
Question 3
[Maximum number: 2]
A long current-carrying wire is at rest in the reference frame S of the laboratory. A positively charged particle P outside the wire moves with velocity v relative to S . The electrons making up the current in the wire move with the same velocity v relative to S .
current-carrying wire
Question 3(b)
(a)
State and explain whether the force experienced by P is magnetic, electric or both
[ 2 ]
Question 3(b)(i)
(i)
in reference frame S .
[ 2 ]
Question 3
Question 3(b)
(a)
A particle of mass m and positive charge q moves on a circular path with speed v in a vacuum. A uniform magnetic field B is directed into the plane of the page.
[ 2 ]
Question 3(b)(i)
(i)
Show that the radius R of the circular path is given by .
[ 1 ]
Question 3(b)(ii)
(ii)
Suggest why the speed of the particle stays constant, even though a force acts on the particle.
[ 1 ]
Question 3(c)
(b)
The particle in (b), now moving in a region of magnetic field in air, follows the path shown.
Explain the shape of this path.
[ 2 ]
Question 3
[Maximum number: 5]
Two oppositely charged parallel plates are a distance 8.0 cm apart. The potential difference between the plates is 120 V . An alpha particle is placed on the positively charged plate and released from rest. Gravity is ignored.
Question 3(b)
Question 3(b)(i)
(a)
(i)
Show that the acceleration of the alpha particle is about .
[ 2 ]
Question 3(c)
(b)
A magnetic field directed into the plane of the page is now established between the plates. An alpha particle enters the region between the plates with a horizontal speed of . The particle is not deflected.
Calculate the magnitude of the magnetic field.
[ 2 ]
Question 3(d)
(c)
The alpha particle in (c) is replaced by an electron. The electron enters the region between the plates with the same velocity as the alpha particle.
Draw, on the diagram, the path of the electron.
[ 1 ]
Question 3
[Maximum number: 1]
Two muons are moving parallel to each other with the same velocity relative to the ground.
In the frame of reference in which the muons are at rest, the force between them is a repulsive electric force.
Question 3(a)
(a)
Explain, for the frame of reference of the ground,
[ 1 ]
Question 3(a)(i)
(i)
why there is an additional magnetic force between the muons.
[ 1 ]
Question 17
[Maximum number: 1]
The diagram shows the path of a particle in a region of uniform magnetic field. The field is directed into the plane of the page.
This particle could be
A
an alpha particle.
B
a beta particle.
C
a photon.
D
a neutron.
Question 17
[Maximum number: 1]
A particle with charge Q is accelerated from rest through a potential difference V over a distance s. The particle then enters a magnetic field of strength P at right angles to the magnetic field direction. What single change will make the radius of curvature of the path of the particle smaller?
A
Increase P
B
Decrease s
C
Increase V
D
Decrease Q
Question 17
[Maximum number: 1]
Electrons in a conductor are moving down the page. A proton outside the wire is moving to the right.
What is the direction of the magnetic force acting on the proton?
A
Down the page
B
Up the page
C
Out of the page
D
Into the page
Question 17
[Maximum number: 1]
The path of three particles with identical magnitude of charge but different mass is shown as they enter a region of uniform magnetic field. The particles have the same initial velocity. The magnetic field is directed into the plane of the paper.
What is the mass of particle X compared to the other particles and what is the sign of the charge on particle X ?
Mass in comparison
Sign of charge
larger
positive
larger
negative
smaller
positive
smaller
negative
Question 17
[Maximum number: 1]
The path of three particles with identical magnitude of charge but different mass is shown as they enter a region of uniform magnetic field. The particles have the same initial velocity. The magnetic field is directed into the plane of the paper.
What is the mass of particle X compared to the other particles and what is the sign of the charge on particle X ?
Mass in comparison
Sign of charge
larger
positive
larger
negative
smaller
positive
smaller
negative