RIO SALADO Physics 112 Midterm Exam Questions and
Answers
Question 1
A positively charged 2mC particle moving in the upward direction at a speed of 20m/s enters a 3.0T field directed into the
page. The particle path curves with a radius of 6cm. What is the mass of the particle
Correct Answer
qvB= mv^2/r
m=qbr/v
m= (2x10^-3) (3T) 0.06)/20
1.8 x10^-5
Question 2
which of the following statements regarding equipotentials and electric fields is accurate
Correct Answer
Electric field lines are perpendicular to equipotentials and electric fields is accurate
Page 1 of 33
,Question 3
The diagram below shows both the electric field lines and the equipotentials near a point source. Which of the following
statements accurately describes the diagram
Correct Answer
The arrows represent the direction of the electric field, the circles represent positions with equal potential, and the source
charge is negative
Question 4
A light bulb connects to a battery. A second, identical light bulb connects in parallel to the first light bulb. The connecting
wires have negligible resistance. When the switch is closed, the original light bulb will
Correct Answer
experience no change in brightness
Question 5
Which of the following statements concerning the structure of an atom is accurate?
Correct Answer
neutrally charged atoms contain equal amounts of protons and electrons
Page 2 of 33
,Question 6
an electron moves through a potential difference of 1500V. The magnitude of the charge in potenial energy experienced
by the electron is
Correct Answer
1500eV
Question 7
Consider a uniform electric field of 50N/C directed towards the east. If the potential measured at some point in the field is
80V, what is the potential at a position 1.0 directly east of that point
Correct Answer
V=Er
80=50 R
R=1.6
1.6-1=.6
50 x .6= 30V
Question 8
The units used to measure the strength of an electric field are
Correct Answer
Newtons per Coulomb
Page 3 of 33
, Question 9
A negatively charged particle moves through various electric fields. Which of the following correctly indicates whether the
negatively charged particle gained or lost energy in each of the following examples
Correct Answer
gained energy
lost energy
gained energy
Question 10
Two parallel wires are oriented vertically (i.e. along the vertical edge of the screen). The wire on the left has the current of
2.0A directed upward. The wire on the right has a current of 4.0A also directed upwards. Which statement is most accurate
Correct Answer
The wire will experience an attracting force
Question 11
The purpose of the battery in the circuit is to act as a source of
Correct Answer
energy
Page 4 of 33
Answers
Question 1
A positively charged 2mC particle moving in the upward direction at a speed of 20m/s enters a 3.0T field directed into the
page. The particle path curves with a radius of 6cm. What is the mass of the particle
Correct Answer
qvB= mv^2/r
m=qbr/v
m= (2x10^-3) (3T) 0.06)/20
1.8 x10^-5
Question 2
which of the following statements regarding equipotentials and electric fields is accurate
Correct Answer
Electric field lines are perpendicular to equipotentials and electric fields is accurate
Page 1 of 33
,Question 3
The diagram below shows both the electric field lines and the equipotentials near a point source. Which of the following
statements accurately describes the diagram
Correct Answer
The arrows represent the direction of the electric field, the circles represent positions with equal potential, and the source
charge is negative
Question 4
A light bulb connects to a battery. A second, identical light bulb connects in parallel to the first light bulb. The connecting
wires have negligible resistance. When the switch is closed, the original light bulb will
Correct Answer
experience no change in brightness
Question 5
Which of the following statements concerning the structure of an atom is accurate?
Correct Answer
neutrally charged atoms contain equal amounts of protons and electrons
Page 2 of 33
,Question 6
an electron moves through a potential difference of 1500V. The magnitude of the charge in potenial energy experienced
by the electron is
Correct Answer
1500eV
Question 7
Consider a uniform electric field of 50N/C directed towards the east. If the potential measured at some point in the field is
80V, what is the potential at a position 1.0 directly east of that point
Correct Answer
V=Er
80=50 R
R=1.6
1.6-1=.6
50 x .6= 30V
Question 8
The units used to measure the strength of an electric field are
Correct Answer
Newtons per Coulomb
Page 3 of 33
, Question 9
A negatively charged particle moves through various electric fields. Which of the following correctly indicates whether the
negatively charged particle gained or lost energy in each of the following examples
Correct Answer
gained energy
lost energy
gained energy
Question 10
Two parallel wires are oriented vertically (i.e. along the vertical edge of the screen). The wire on the left has the current of
2.0A directed upward. The wire on the right has a current of 4.0A also directed upwards. Which statement is most accurate
Correct Answer
The wire will experience an attracting force
Question 11
The purpose of the battery in the circuit is to act as a source of
Correct Answer
energy
Page 4 of 33
