Electricity and magnetism are separate yet interconnected phenomena. Which of the following options does BEST support the idea that electricity and magnetism are interconnected? (A) Electricity is the phenomenon of electric charges, whether they are stopped or moving.
(B) When a particle is stationary or stopped, it has an electric field, yet if the charge is moving, it also generates a magnetic field.
{C) Any magnetic particle or object has a "north" and "south" pole, with the directions based on the orientation of the Earth's magnetic field.
(D) Magnetism, like electricity, also has associated units of measurement, such as Tesla (T).

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.

The voltage applied across a given parallel-plate capacitor is doubled. how is the energy stored in the capacitor affected?