samplex6 - University of the Philippines College of Science...

University of the Philippines
College of Science
Physics 72
Set A
Final Exam
First Semester, AY 2015–2016
Name: Instructor:
Section/Class Schedule: Student Number:
Course: College:

Final Exam First Semester, AY 2015–2016 Physics 72
INSTRUCTIONS: Choose the best answer and shade the corresponding circle on your answer
sheet. To change your answer, cross-out and sign your original answer and then shade your
new answer. No computational devices allowed (e.g. calculators, mobile phones). Any form
of cheating in examinations or any act of dishonesty in relation to studies, such as plagiarism,
shall be subject to disciplinary action. Following instructions is part of the exam.
Useful formulas:
Area Volume
Sphere (radius= r ) 4 πr
2 4
3
πr
3
Cylinder (radius= r , height= h ) 2 πr
2
+ 2 πrh πr
2
h
sin( π/ 3) = cos( π/ 6) =
√
3 / 2
cos( π/ 3) = sin( π/ 6) = 1 / 2
sin( π/ 4) = cos( π/ 4) =
√
2 / 2
Useful constants:
e - 1 . 60 × 10
- 19
C
m
e
9 . 1 × 10
- 31
kg
0
8 . 854 × 10
- 12
C
2
/Nm
2
k 8 . 988 × 10
9
Nm
2
/C
2
1. what a qt! A negative test charge is placed a distance r from a positive charge q . Which of
the following statements is/are TRUE regarding the electric field of q , E , and the electric
force, F
t
, on the negative test charge?
I. F
t
is in the same direction as E .
II. F
t
and E are in opposite directions.
III. At r , | E | ∝ | F
t
| .
Solution: II and III
A – 2

Final Exam First Semester, AY 2015–2016 Physics 72
2. Moligoyong arrow! Shown are the electric
field lines due to three point charges X, Y, and
Z. Which of the following statements is TRUE
about the direction of the electric field vector at
point P and the nature of the charges?
3. diPole McCartney. An electric dipole is immersed in a
uniform electric field as shown. Which of the following
statements is TRUE regarding the dipole’s motion?
A – 3

Final Exam First Semester, AY 2015–2016 Physics 72
For the next three items, consider a solid conduct-
ing sphere, with charge - 2 Q and radius R , en-
closed in a rectangular conductor, with charge + Q ,
as shown.