Download Chapter 6 - Portal UniMAP

DKT113 Engineering Physics
Semester 1 Session 2010/11
TUTORIAL 6
1. (a) What is electric charge?
(b) State the principle of law of charges or charge-force law. From Figure below,
explain what happened to the two charges given and also the relationship
based on law of charges or charge- force law.
Figure 1
(c) Name THREE (3) types of electrostatic charging.
(d) State Coulomb’s Law with its equation.
2. Figure 2 shows the three charges of q1=+10µC, q2=+5µC and q3=-8µC are fixed
along a straight line. Calculate the resultant force on the
a) Charge at +5µC
b) Charge at +10µC
q1=+10µC
q2=+5µC
2 cm
q3=8µC
2 cm
Figure 2
DKT113 Engineering Physics
Semester 1 Session 2010/11
3. Find the magnitude and direction of the electric field strength at the point P due to
the point charges at A and B as shown in the Figure 3.
P
10 cm
10 cm
B
-8nC
A
+2nC
Figure 3
+2µC
4.
The charges
q1  20C , q2  15C , q3  15C and q4  10C are
arranged as shown in Figure 4. Calculate the resultant electric force and direction which
acts on charge q4. [Given o = 8.85 x 10-12C2 / N.m2]
q1
q2
q4
q3
a= 4 cm
b = 5 cm
Figure 4
5. Two point charges of -1.0nC and +2.0nC are separated by a distance of 0.3m,
what is the electric force on each particle?
q1 = - F12
1nC
q2 = F21
+2nC
0.3m
Figure 5
DKT113 Engineering Physics
Semester 1 Session 2010/11
6. Find the electric field at point O for the charge configuration shown in Figure 6
Figure 6
9. Draw the pattern of electric field line for:
(i)
Like point charges
(ii)
Unequal like point charges
10. Draw the electric field line pattern for object below:
i)
+
-
ii)
-
+
iii)
-
-
iv)
+
+
11. An electron is moved from point A to point B and then to point C along two legs of
an equilateral triangle with sides of length 0.25 m Figure 8. If the horizontal electric field is
15 V m,
(a) what is the magnitude of the work required?
(b) What is the potential difference between points A and C?
(c) Which point is at a higher potential?
Figure 7