Coulomb's Law: One point charge +Q is placed at the center of a square, and a second point charge -Q is placed at the upper-left corner of the square. It is observed that an electrostatic force of magnitude 2.0 N acts on the positive charge at the center. Now a third charge -Q is placed at the lower-left corner of the square, as shown in the figure. What is the magnitude of the net force that acts on the center charge now?
A. 0.0 N
B. 2.8 N
C. 4.0 N
D. 5.3 N
Answer: B
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An atom can get the energy that moves an electron to a higher energy level by:
A) absorbing a photon of electromagnetic radiation. B) preventing collisions with other atoms. C) moving the electron to a tightly bound level. D) transferring the electron to the ground state.
Single-Slit Diffraction: A beam of monochromatic light passes through a slit that is 11.0 ?m wide. If the first order dark fringe of the resulting diffraction pattern is at an angle of 4.31° away from the centerline, what is the wavelength of light?
A. 827 nm B. 301 nm C. 602 nm D. 402 nm E. 201 nm
Order these cosmological events in order from earliest to latest.
A) formation of the first atomic nuclei, formation of the first neutral atoms, formation of the first subatomic particles, formation of the first galaxies B) formation of the first subatomic particles, formation of the first atomic nuclei, formation of the first neutral atoms, formation of the first galaxies C) formation of the first galaxies, formation of the first neutral atoms, formation of the first atomic nuclei, formation of the first subatomic particles D) formation of the first subatomic particles, formation of the first neutral atoms, formation of the first atomic nuclei, formation of the first galaxies E) formation of the first neutral atoms, formation of the first subatomic particles, formation of the first atomic nuclei, formation of the first galaxies F) formation of the first atomic nuclei, formation of the first subatomic particles, formation of the first neutral atoms, formation of the first galaxies
Stephen Hawking predicted that black holes can "evaporate" by emitting what we now call Hawking radiation. What does it mean for a black hole to "evaporate"?
A) The black hole loses its electric charge. B) The black hole's mass is gradually reduced. C) The black hole itself remains unchanged in mass, but it is able to send radiation out into the universe. D) Any matter that surrounds the black hole is heated to the point where it becomes a gas, if it wasn't already.