Chemistry Expert Answers & Study Resources

  1) A helium-neon laser emits light at 632.8 nm. If the laser emits 1.82 ? 1017 photons/second, what is its power output in mW? A) 57.2 mW B) 28.6 mW C) 37.2 mW D) 45.7 mW 2) Find the de Broglie wavelength of a 1.30 kg object moving a 28.10 m/s. A) 1.81 × 10-35 m B).

  1) Increasing the kinetic energy of an electron increases its de Broglie wavelength. 2) The frequency of light is the number of photons per second that it carries. 3) Photons all travel at the speed of light so they must all have the same energy. 4) An electron and a photon having the.

  1) Suppose you have two positive point charges and want to move them closer together. To do the least amount of work, you should move them directly toward each other; any other path will require more work because the charges must move through a greater distance. 2) Two equal positive charges.

Situation 27.1 A proton (rest energy = 938 MeV) has a speed of 0.80 c. 11) In Situation 27.1, the ratio of the kinetic energy of the proton to its rest energy is closest to: A) 0.60 B) 0.67 C) 0.80 D) 1.2 E) 1.7 12) In Situation 27.1, the momentum of the proton in kg ? m/s.

  1) Consider two synchronized, extremely accurate clocks. One clock is on the ground, the other is placed in a jet and flown once around the world, then taken out of the plane and compared with the ground clock. Will the clock on the jet read a time earlier than, the.

11) A charged particle of mass  0.0040 kg is subjected to a 4.0 T magnetic field that acts at a right angle to its motion. If the particle moves in a circle of radius 0.10 m at a speed of 2.0 m/s, what is the magnitude of the charge on.

  1) In a purely resistive AC circuit, when the voltage is at its maximum, the current is at its maximum value as well. 2) A step-up transformer lowers current but raises voltage. 3) Power loss in the transmission lines depends linearly on the current. 4) The AC current through a capacitor lags the.

11) What mass of 14C (half-life = 5730 years) do you need to provide a decay rate of 280.0 Bq? A) 1.70 × 10-12 kg B) 5.38 × 10-19 kg C) 3.84 × 10-20 kg D) 8.68 × 10-13 kg 12) Today, uranium contains 0.72% 235U  (half-life = 0.70 billion years) and 99.28% 238U (half-life.

  1) Why is it that electrons rather than positive ions flow from a wire? 2) Lightening is a discharge of electrons that commonly is greater than is needed to neutralize a positive charge. A series of strokes, each in the opposite direction of the previous stroke, occur to overcome this excessive.

  1) If a magnetic compass is placed between the plates of a fully charged capacitor, the compass will align itself along the electric field lines. 2) A small plastic ball has an excess negative charge on it. If a magnet is placed close to this ball, it will either attract or.

  1) Each of the resistors in the circuit shown have a resistance of 160.0 Ω. What is the equivalent resistance of the circuit? A) 400.0 Ω B) 640.0 Ω C) 480.0 Ω D) 160.0 Ω 2) The resistors in the circuit shown each have a resistance of 600 Ω. What is the equivalent resistance of.

  1) What is the wavelength of the light emitted by atomic Hydrogen according to Balmer's formula with m = 3  and n = 8? A) 955 nm B) 389 nm C) 1950 nm D) 384 nm 2) What is the frequency of the light emitted by atomic Hydrogen according to Balmer's formula with m =.

  1) It is impossible for an electron to lose its spin angular momentum. 2) All stationary states of the hydrogen atom for which n = 4 have the same energy. 3) The electron cloud of an atom is formed because the electron spreads out in space. 4) When collisional excitation occurs, an electron.

11) The 60 Hz ac source of a series circuit has a voltage amplitude of 120 V. The capacitive and inductive reactances are 980 Ω  and 270 Ω, respectively. The resistance is 550 Ω. In the figure, the capacitance, in μF, is closest to: A) 2.7 B) 5.2 C) 7.8 D) 10 E) 16 12) The.

  1) The resistivity of gold is 2.44 × 10-8 Ω·m at a temperature of 20°C. A gold wire,  0.5 mm in diameter and  44 cm long, carries a current of  380 ma. The number of electrons per second passing a given cross section of the wire is closest to: A) 2.4.

11) An atom has completely filled inner shells and a single valence electron in an excited p state. The filled inner shells have an orbital momentum equal to zero. The magnitude of the orbital angular momentum of the atom is closest to: A) 1.0 B) 1.2 C) 1.4 D) 1.7 E).

21) An electron has the same de Broglie wavelength as a  1.8 eV photon. The speed of the electron is closest to: A) 1100 m/s B) 980 m/s C) 910 m/s D) 840 m/s E) 770 m/s 22) A molecule of roughly spherical shape has a mass of  1.80 × 10-25 kg and a diameter of 0.6.

  1) Approximately what fraction of the volume of an atom is made up of the nucleus? A) 10-15 B) 10-6 C) 10-1 D) 10-24 2) The first nuclear reaction observed saw an alpha particle (Z = 2) interact with a nitrogen nucleus in air (Z = 7) to produce a proton. The energy of the.

11) A multiloop circuit is given. It is not necessary to solve the entire circuit. In the figure shown, the emf ε1 is closest to: A) -28 V B) 28 V C) 68 V D) 72 V E) -72 V 12) A multiloop circuit is given. It is not necessary to solve the entire circuit. In.

5) How many 3d electron states can an atom have? A) 0 B) 4 C) 6 D) 8 E) 10 6) Neon has 10 electrons. The element of next higher Z that has chemical properties very similar to those of neon has Z equal to: A) 11 B) 17 C) 18 D) 19 E) 36 7) The correct ground state electron configuration.

  1) The majority of known nuclei are stable. 2) If half of a radioactive substance decays in the first 10 s, the other half will decay in the next 10 s. 3) The binding energy per nucleon increases steadily with the mass number of the nucleus. 4) In beta-minus decay, the number of.

  1) In a spaceship that is approaching Earth at 80% the speed of light, the captain shines a laser beam directly toward Earth. The captain measures the laser light's speed to be 3.00 × 108 m/s and the receiving station on Earth will measure exactly the same speed for this.

6) Draw a circuit with two batteries, a resistor between them, and a capacitor in parallel with the resistor. The batteries are connected negative pole to positive pole. A) B) C) D) 7) How are the two batteries in the figure connected? State whether they are in parallel or in series.

  1) If a circuit doubles its peak voltage, what happens to its rms voltage? 2) Why is it not possible to have an LC circuit oscillate if the frequency of the signal constantly changes? 3) For circuits with either an inductor and/or a capacitor, the current gets out of phase with the.

  1) A circular conducting loop with a radius of 1.00 m and a small gap filled with a 10.0 Ω resistor is oriented in the xy-plane. If a magnetic field of 2.0 T, making an angle of 30º with the z-axis, increases to 9.0 T in 2.0 s, what is.

11)  14C and 14N both contain 8 neutrons in their nuclei. 12) All atoms of a given element contain exactly the same number of protons in their nucleus, but they may have different numbers of neutrons. 13) No two distinct atoms produce the same emission spectrum. 14) In spontaneous emission, the electrons all.

21) An 800 kHz radio signal is detected at a point  2.1 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 800 mV/m. Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground.

11) A device with a resistance of 200.0 kΩ is connected to a 9.0 V battery. How much power does the device use? A) 0.41 mW B) 16,000 kW C) 0.045 mW D) 1800 kW 12) A jeweler needs to electroplate gold (atomic mass 196.97 u) onto a bracelet. He knows that the charge carriers.

11) A photocathode whose work function is  2.5 eV is illuminated with white light that has a continuous wavelength band from  360 nm to 700 nm. The stopping potential for this white light illumination is closest to: A) 0.94 V B) 0.85 V C) 1.0 V D) 1.1 V E) 1.2 V 12) A photocathode has.

  1) Why do heavy nuclei contain more neutrons than protons? A) Neutrons dilute the electric repulsion of the protons. B) Neutrons are lighter than protons. C) Neutrons are heavier than protons D) Neutrons are radioactive, and so are heavy nuclei. 2) A positron (or antielectron) is made to stop in a sample of matter. Soon.

  1) According to Lenz's law, the induced current in a circuit must flow in such a direction to oppose the flux through that circuit. 2) You are pulling a rectangular coil through a uniform static magnetic field that extends well beyond the boundary of the coil. The faster you pull this.

Chapter 27   Relativity   27.1   Quantitative   1) Two fixed navigation beacons mark the approach lane to a star. The beacons are in line with the star and are  40 Mm apart. A spaceship approaches the star with a relative velocity of  0.30 c and passes the beacons. The passage of the ship between.

10) In the figure, a straight wire carries a current I. The wire passes through the center of a toroidal coil. The current is quickly reduced to zero. The induced current through the resistor R is: A) zero B) from a to b C) from b to a 11) In the figure, a C-shaped.

20) A loop of wire is situated inside a large solenoid, with the plane of the loop initially perpendicular to the axis of the solenoid. Current can be made to flow through the loop of wire if A) a constant current is flowing through the solenoid wire. B) the current flowing through.

  1) As current flows through a uniform wire, the wire gets hotter because the electrons slow down and therefore transform their lost kinetic energy into thermal energy in the wire. 2) When current is flowing in a metal, the electrons are moving at nearly the speed of light. 3) In the metal.

1) In 1869 Friedrich Miescher isolated a substance called “nuclein” from pus from soiled bandages that was a(n) A. acidic, phosphorus-rich substance B. basic, phosphorus-rich substance C. amino acid-rich substance D. phospholipid-rich substance 2) The basic principles of genetics attributed to Gregor Johann Mendel are: A. the laws of segregation and independent assortment B. the Punnett square C..

  1) By how much are the electric and magnetic fields out of phase in an electromagnetic wave? 2) For electromagnetic waves, the electric and magnetic fields are often given in the form of sine waves. Explain how this model of electromagnetic waves does not violate the conservation of energy, especially when.

  1) A particle with a charge of 1 C experiences a force FBin a magnetic field. A second particle follows it at the same velocity. If the second particle has a charge of -2C, what force does it experience? 2) A horseshoe magnet has straight sides as shown. An electron travelling.

11) Modern nuclear bomb tests have created an extra high level of 14C in our atmosphere. When future archaeologists date samples from this era, without knowing of this testing, will their dates be too young?  Too old? Correct? If correct, why? A) too young B) too old C) Correct, since 14C from bomb.

31) An electron is confined in a one-dimensional box. Two adjacent allowed energies of the electron are 2.8 × 10-19 J and 3.5 × 10-19 J. What is the length of the box? A) 1.9 × 10-9 m B) 9.3 × 10-10 m C) 1.1 × 10-9 m D) 2.3 × 10-9 m 32) Electrons.

10) A long straight wire has a constant current flowing to the right. A square ring is situated above the wire, and also has a constant current flowing through it (as shown). Which of the following statements is true? A) The net magnetic force on the ring is upward, and there.

1) An alternating current is supplied to a lightbulb, which strobes. A motor rotates a white fan (with one blade painted red) at 504 Hz in the light from the strobing bulb, and the fan appears to stand still. At 252 Hz the red blade alternates between two positions that.

1) Alpha particles (charge = +2e, mass = 6.68 × 10-27 kg) are accelerated in a cyclotron to a final orbit radius of 0.30 m. The magnetic field in the cyclotron is 0.80 T. The period of circular motion of the alpha particles is closest to: A) 0.16 μs B) 0.25 μs C).

11) A uniform electric field perpendicular to a spherical surface of radius 5.00 cm is increasing at a rate of 4.0 V/m · µs. Find the displacement current through the spherical surface. A) 1.11 μA B) 142 μA C) 1853 nA D) 0.071 mA 12) If the peak electric field in an electromagnetic wave is.

21) In an "atom smasher," two particles collide head on at relativistic speeds. If the velocity of the first particle is 0.741 c to the left, and the velocity of the second particle is 0.543 c to the right (both of these speeds are measured in Earth's rest frame), how.

  1) Four charged particles (two having a charge +Q and two having a charge -Q) are distributed on the xy-plane, as shown below. Each charge is equidistant from the origin. The voltage is zero at infinity. The voltage at location P, which is on the z axis, is A) zero. B) positive. C).

9) A photon collides with an electron that is initially at rest, causing the electron to move. After the collision, the wavelength of the photon is A) greater than its initial value. B) equal to its initial value. C) less than its initial value. 10) Increasing the brightness of a beam of light without.

  1) Ohm's law is a fundamental law of physics and is therefore obeyed by all materials. 2) If the graph of the current through a resistor as a function of the potential difference across it is a straight line with a positive slope passing through the origin, the resistor obeys Ohm's.

7) A person buys a SUV and discovers that it is too long to fit  in the garage (the length of the SUV is 1.3 times the length of the garage). He decides to drive the SUV into the garage at a speed of 0.99 c. Which statement is true? A).

    1) Illuminating a particular metal surface with a helium-neon laser results in the emission of photoelectrons. Will the kinetic energy of the photoelectrons increase if you increase the laser's power? Support your answer. 2) A friend in your physics class tells you that illuminating a surface with any laser will result.