Download Homework 4 - Physics at SMU

9/29/2014
Print Assignment: Fall 2014 - Homework 4 ::true
Question 1
Figure 24-23 shows four pairs of charged particles. For each pair, let V = 0 at infinity
and consider Vnet at points on the x axis.
For which pairs is there a point at which Vnet = 0 between the particles?
(1)
(2)
(3)
(4)
None
For which pairs is there a point at which Vnet = 0 to the right of the particles?
(1)
(2)
(3)
(4)
None
At such a point is
due to the particles equal to zero?
Yes
No
http://edugen.wileyplus.com/edugen/shared/assignment/test/agprint.uni?numberQuest=true&titleType=true
1/4
9/29/2014
Print Assignment: Fall 2014 - Homework 4 ::true
For each pair, are there off-axis points (other than at infinity) where Vnet = 0? Mark the
pairs where this is true.
(1)
(2)
(3)
(4)
None of the pairs exhibit this quality.
Question 2
The electric potential difference between the ground and a cloud in a particular
thunderstorm is 2.2 x 109 V. What is the magnitude of the change in the electric
potential energy (in eV) of an electron that moves between the ground and the cloud?
*1
eV
Significant digits are disabled; the tolerance is +/-2%
Question 3
An electron is projected with an initial speed of 3.6 x 105 m/s directly toward a proton
that is fixed in place. If the electron is initially a great distance from the proton, at what
distance from the proton is the speed of the electron instantaneously equal to 6 times
the initial value?
Number
*1
Units
Significant digits are disabled; the tolerance is +/-2%
Question 4
Figure 25-18 shows plots of charge versus potential difference for three parallel-plate
capacitors that have the plate areas and separations given in the table. Which plot goes
with which capacitor?
http://edugen.wileyplus.com/edugen/shared/assignment/test/agprint.uni?numberQuest=true&titleType=true
2/4
9/29/2014
Print Assignment: Fall 2014 - Homework 4 ::true
capacitor 1
capacitor 2
capacitor 3
1. plot a
2. plot b
3. plot c
Question 5
A parallel-plate capacitor has circular plates of 8.40 cm radius and 1.74 mm separation.
(a) Calculate the capacitance in picofarads. (b) What charge in nanocoulombs will
appear on the plates if a potential difference of 123 V is applied?
(a) Number
*1
Units
(b) Number
*2
Units
*1 - significant digits are disabled; the tolerance is +/-2%
*2 - significant digits are disabled; the tolerance is +/-2%
Question 6
The parallel plates in a capacitor, with a plate area of 9.70 cm2 and an air-filled
separation of 3.10 mm, are charged by a 7.90 V battery. They are then disconnected
from the battery and pulled apart (without discharge) to a separation of 6.80 mm.
Neglecting fringing, find (a) the potential difference (in V) between the plates, (b) the
initial stored energy, (c) the final stored energy, and (d) the work required to separate
the plates.
(a) Number
*1
Units
http://edugen.wileyplus.com/edugen/shared/assignment/test/agprint.uni?numberQuest=true&titleType=true
3/4
9/29/2014
Print Assignment: Fall 2014 - Homework 4 ::true
(b) Number
*2
Units
(c) Number
*3
Units
(d) Number
*4
Units
*1
- significant digits are disabled; the tolerance is +/-2%
*2
- significant digits are disabled; the tolerance is +/-2%
*3 - significant digits are disabled; the tolerance is +/-2%
*4 - significant digits are disabled; the tolerance is +/-2%
Question 7
A certain parallel-plate capacitor is filled with a dielectric for which κ = 4.97. The area of
each plate is 0.0262 m2, and the plates are separated by 1.11 mm. The capacitor will
fail (short out and burn up) if the electric field between the plates exceeds 150 kN/C.
What is the maximum energy that can be stored in the capacitor?
Number
*1
Units
Significant digits are disabled; the tolerance is +/-2%
http://edugen.wileyplus.com/edugen/shared/assignment/test/agprint.uni?numberQuest=true&titleType=true
4/4