Exam 1 (clickers) Flashcards
The entropy of a system can decrease _______.
A. Only if the system is completely isolated from the surrounding environment
B. Anytime regardless of what happens in the surrounding environment
C. Never
D. Only if the entropy of the surrounding environment increases by a greater amount
D. Only if the entropy of the surrounding environment increases by a greater amount
Initially, there are more marbles in box 1 and fewer in box 2. When the system reaches thermodynamic equilibrium, which box would have more marbles?
A. Box 1
B. Box 2
C. Neither - they should have equal numbers of marbles
D. It’s impossible to determine
C. Neither - they should have equal numbers of marbles
According to the Boltzmann distribution, the probability that a system will have a particular arrangement of energy _____ as the energy of the arrangement increases (for a given temperature).
A. Increases
B. Decreases
C. Doesn’t change
B. Decreases
As temperature increases, what happens to the probability that a system will have a particular value of energy?
A. The probability increases for high energies but decreases for low energies
B. The probability increases for all energies
C. The probability decreases for all energies
D. The probability doesn’t change
A. The probability increases for high energies but decreases for low energies
A system has two possible energy states, E0 and E1 (with E1 > E0). As the gap between these energy states grows (E0 and E1 get further apart) while the temperature stays constant, then the probability that the system will have energy E1 compared to the probability the system will have energy E0 __________.
A. Increase
B. Decrease
C. Stays the same
D. Approaches 50% (so E0 and E1 are equally likely)
B. Decrease
How are probability and energy related? (Boltzmann)
inversely proportional
As probability increases, energy decreases
At a high energy, increasing the probability will ______ the temperature.
Increase
At a low energy, increasing the probability will ____ the temperature.
Decrease
An electric field is present at a point in space. A small charge q is placed at the point where the electric field is present. Which statement is true?
i. Increasing the charge q will increase the force felt by that charge from the electric field
ii. Increasing the charge q will decrease the strength of the electric field at that point
A. Only i
B. Only ii
C. Both i and ii
D. Neither i nor ii
A. i
Which of the following is not an example of a vector field?
A. Temperature
B. Electric field
C. Gravitational field
D. Wind velocity
A. Temperature
A wool sweater and two balloons are all electrically neutral. The two balloons are rubbed on the wool sweater, after which each balloon has a net charge of -3 nC. What is the final net charge of the sweater?
A. -3 nC B. -6 nC C. +3 nC D. +6 nC E. 0 nC - the sweater is still electrically neutral
D. +6 nC
(the balloon has 6 + charges and 6 - charges. you can tell bc each of the balloons gained net charges of -3 uC so there must have been 6 + charges on the sweater)
Does a test charge used to measure electric field always have to be positive?
Yes
The electric field of a positive infinite line of charge______
A. Points perpendicularly away from the line of charge and decreases in strength at larger distances
B. Points parallel to the line of charge and decreases in strength at larger distances from the line charge
C. Points perpendicularly away from the line of charge and increases in strength at larger distances from the line charge
D. Points parallel to the line of charge and increases in strength at larger distances from the line charge
A. Points perpendicularly away from the line of charge and decreases in strength at larger distances
A square plate of metal has a uniform surface charge density. If the area of the metal plate is doubled while keeping the surface charge density the same, then the total charge of the metal plate _________
A. Increases by a factor of 2
B. Decreases by a factor of 2
C. Increases by a factor of 4
D. Decreases by a factor of 4
A. Increases by a factor of 2
A thin spherical shell of uniform charge does not have which of the following properties?
A. The electric field outside of the shell looks like the electric field of a point charge
B. The electric field everywhere inside the shell is 0
C. The electric field outside of the shell only exists at some points in space and not all points in space
D. The electric field outside of the shell is perpendicular to the surface of the shell
C. The electric field outside of the shell only exists at some points in space and not all points in space
