The Bohr model pictures a hydrogen atom in its ground state as a proton and an electron separated by the distance a0 = 0.529 × 10^−10 m. The electric potential created by the proton at the position of the electron is
A space station in the form of a large wheel, 120 m in diameter, rotates to provide an "artificial gravity" of 3.00 m/s2 for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.
A car travels counterclockwise around a flat circle of radius 0.25 km at a constant speed of 20 m/s. When the car is at point A as shown in the figure, what is the car's acceleration?<img src="https://sciemce.com/files/2/ppg__cognero__Chapter_4_Two_and_Three_Dimensional_Motion.__media__06fe6857-36c4-4776-8e21-675a1d60c9fc.PNG" style="vertical-align: 0px;" width="186px" height="156px" />
A large jetliner with a wingspan of 51.0 m flies horizontally and due north at a speed of 440 m/s in a region where the magnetic field of the earth is 48.4 µT directed 30.0° below the horizontal. What is the magnitude of the induced emf between the ends of the wing?
At a certain time, the average size of a transistor in a microprocessor was 250 nanometers. A human hair has a diameter of 70 microns (micrometers). How many transistors fit across a human hair?
A flat coil of wire consisting of 20 turns, each with an area of 50 cm2, is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 2.0 T to 6.0 T in 2.0 s. If the coil has a total resistance of 0.40 Ω, what is the magnitude of the induced current?
Uniform Electric Fields: A uniform electric field, with a magnitude of 500 V/m, is points in the +x direction. If the potential at x = 5.0 m is 2500 V, what is the potential at x = 2.0 m?
A little magnetic compass has a needle whose tips are clearly labeled N and S. The compass is placed next to a single circular loop of wire lying flat on a wooden table. The current in the loop is clockwise. What happens?
Phase Angles: A series ac circuit has a resistance of 2.0 kΩ, a capacitance of 8.0 μF, and an inductance of 9.0 H. If the frequency of the alternating current is 4.0/π kHz, by what angle does the voltage lead the current?
The speed of sound in the air inside a 0.640-m long gas column is 340 m/s. What is the fundamental resonant frequency of this air column if it is (a) open at one end and closed at the other end? (b) open at both ends?
A block is pushed up a 20.0° frictionless incline with an initial speed 12.0 m/s. (a) How high up the plane does the block slide before coming to rest? (b) How much time does it take to return to its starting position?
In chapter Q1, we noted that the speed of sound in air depends on the air’s temperature (increasing as the square root of the air temperature). Suppose a flute player tunes a flute that has been sitting in a cold automobile. As the flute warms up to room temperature, does it go sharp (A) or flat (B)?
A convex mirror has a focal length of −20 cm. What is the position of the resulting image (in cm) if the image is upright and four times smaller than the object?
Thin Lenses: A convex lens has focal length f. If an object is placed at a distance beyond 2f from the lens on the principal axis, the image is located at a distance from the lens
A thermometer is made such that the freezing point of water is defined to be 60.0°H and the boiling point of water at sea level is defined to be 520°H. What is the Celsius temperature at 240°H?
An alpha particle is moving at a speed of 5.0 × 105 m/s in a direction perpendicular to a uniform magnetic field of strength 0.040 T. The charge on an alpha particle is 3.2 × 10-19 C and its mass is 6.6 × 10-27 kg
A metal blade (length = 80 cm) spins at a constant rate of 10 radians/s about a pivot at one end. A uniform magnetic field of 2.0 mT is directed at an angle of 30° with the plane of the rotation. What is the magnitude of the potential difference between the two ends of the blade?
You perform Compton scattering experiments with X-rays of a fixed wavelength. In one experiment you scatter the X-rays from free electrons. In the second experiment you scatter the X-rays from protons instead
Kirchhoff's Rules: A multiloop circuit is shown in the figure. Find the current I2 if the batteries are ideal. (It is not necessary to solve the entire circuit.)<img src="https://sciemce.com/files/4/ppg__cp1pbb0313192044__f258g1q14g1.jpg" alt="" style="vertical-align: 0.0px;" height="310" width="394" />
If a stone is dropped so that the initial gravitational potential energy of the system stone-Earth is 100 J but it reaches the ground with a kinetic energy of only 75 J, this is a violation of the principle of conservation of energy
Density: The average density of blood is 1.06 × 103 kg/m3. If you donate a pint of blood to the Red Cross, how many grams of blood have you donated? (2.00 pt = 1.00 qt, 1.00 L = 1000 cm3, 1.00 qt = 0.947 L, and density is mass per unit volume.)
Two harmonic sound waves reach an observer simultaneously. The observer hears the sound intensity rise and fall with a time of 0.200 s between the maximum intensity and the succeeding minimum intensity
A mass is pressed against (but is not attached to) an ideal horizontal spring on a frictionless horizontal surface. After being released from rest, the mass acquires a maximum speed v and a maximum kinetic energy K
A coating is being applied to reduce the reflectivity of a pane of glass to light with a frequency of 5.75 × 1014 Hz that is incident normally on the pane