1) A positively charged glass rod attracts object X. The net charge of object X
a) may be zero or negative
b) may be zero or positive
c) must be negative
d) must be positive
2) What is the net electrical charge on a magnesium ion that is formed when a neutral magnesium atom loses two electrons?
a) –3.2 × 10^–19 C b) +1.6 × 10^–19 C
c) –1.6 × 10^–19 C d) +3.2 × 10^–19 C
3) If the charge on each of two small charged metal spheres is doubled and the distance between the spheres remained fixed, the magnitude of the electric force between the spheres will be
a) the same b) twice as great
c) ½ as great d) 4 times as great
4) An electroscope has been positively charged so the flaps are up. Then a positively charged rod is brought near the top of the electroscope without touching. Will the flap
a) remain the same
b) open up even more
c) will go down
5) A particle with a charge of 2.5x10^-6 move from point A to point B. There is an Electric field between A and B. 6.3x10^-4 J of work is required to move the charged particle from A to B. What is the potential difference between point A and B?
a) 1.6x10^-9 V b) 4.0x10^-3 V
c) 2.5x10^2 V d) 1.0x10^14 V
6) Oil droplets may gain electrical charges as they are projected through a nozzle. Which quantity of charge is not possible on an oil droplet?
a) 8.0×10^–19 C b) 3.2 × 10^–19 C
c) 4.8 × 10^–19 C d) 2.6 × 10^–19 C
7) If an object has a net negative charge of 4.0 coulombs, the object possesses
a) 6.3 × 10^18 more electrons than protons
b) 2.5 × 10^19 more electrons than protons
c) 6.3 × 10^18 more protons than electrons
d) 2.5 × 10^19 more protons than electrons
8) Which graph best represents the electrostatic force between an alpha particle with a charge of +2 elementary charges and a positively charged nucleus as a function of their distance of separation?
a) b)
c) d)
9) In the diagram below, P is a point near a negatively charged sphere.
Which vector best represents the direction of the electric field at point P?
10) Identical Sphere A and B has a charge of -3x10^-6 C. Both spheres were brought into contact the separated. The charge on sphere A is
a) 0 C b) +3x10^-6 C
c) -3x10^-6 d) -6x10^-6 C
11) A spring with a spring constant of 4.0 N/m is compressed by a force of 1.2N. What is the total elastic potential energy stored in this compressed spring?
a) 0.18 J b) 0.60 J
c) 0.36 J d) 4.8 J
12) Centripetal force Fc acts on a car going around a curve. If the speed of the car were twice as great, the magnitude of the centripetal force necessary to keep the car moving in the same path would be
a) Fc b) Fc/2
c) 2Fc d) 4Fc
13) A positively charged rod is held near, but does not touch, a neutral electroscope. The flap goes up
Charge on the top becomes
a) + and the flap becomes +
b) – and the flap becomes –
b) + and the flap becomes –
d) – and the flap becomes +
14) The energy required to move one elementary charge through a potential difference of 5.0 volts is
a) 8.0 J b) 5.0 J
c) 8.0x10^-19 J d) 1.6x10^-19J
15) How much electrical energy is required to move a 4.00-microcoulomb charge through a potential difference of 36.0 volts?
a) 9.00 × 10^6 J b) 1.44 × 10^–4 J
c) 144 J d) 1.11 × 10^–7 J
16) A beam of electrons is directed into the electric field between two oppositely charged parallel plates, as shown in the diagram below.
The electrostatic force exerted on the electrons by the electric field is directed
a) toward the bottom of the page
b) toward the top of the page
c) into the page
d) out of the page
17) A skater increases her speed uniformly from 2.0 meters per second to 7.0 meters per second over a distance of 12 meters. The magnitude of her acceleration as she travels this 12 meters is
a) 1.9 m/s^2 b) 2.4 m/s^2
c) 2.2 m/s^2 d) 3.8 m/s^2
18) What is the electrostatic force between 2 protons which are separated by a distance of 1.0x10^-6 meters?
a) 2.3x10^-16 N; repulsive
b) 2.3x10^-16 N; attractive
c) 9.0x10^21 N; repulsive
d) 9.0x10^21 N; attractive
19) Two protons are located one meter apart.
Compared to the gravitational force of attraction between the two protons, the electrostatic force between the protons is
a) stronger and repulsive
b) weaker and repulsive
c) stronger and attractive
d) weaker and attractive
20) The diagram below shows two identical metal spheres, A and B, separated by distance d. Each sphere has mass m and possesses charge q
Which diagram best represents the electrostatic force Fe and the gravitational force Fg acting on sphere B due to sphere A?
21) The diagram below shows three neutral metal spheres, x, y, and z, in contact and on insulating stands.
Which diagram best represents the charge distribution on the spheres when a positively charged rod is brought near sphere x, but does not touch it?
a)
b)
c)
d)
Long Questions
1) The centers of two small charged particles are separated by a distance of 1.2 × 10^–4 m.
The charges on the particles are +8.0 × 10–19 coulomb and +4.8 × 10–19 coulomb, respectively.
a) Calculate the magnitude of the electrostatic force between these two particles. [Show all work, including the equation and substitution with units.]
b) Sketch a graph showing the relationship between the magnitude of the electrostatic force between the two charged particles and the distance between the centers of the particles.
c) On the diagram, draw at least four electric field lines in the region between the two positively charged particles.
2) A projectile is fired from the ground with an initial velocity of 250. meters per second at an angle of 60.° above the horizontal.
a) Determine at what time will the projectile reach its peak?
b) Determine the horizontal component of the initial velocity.
c) Explain why the projectile has no acceleration in the horizontal direction. [Neglect air friction.]