4) why doesn't the existence of a threshold frequency for the photoelectric effect make sense from the point of view of a continuous wave model of light?

4b) how does the concept of a photon explain the existence of a threshold frequency?

An airplane with a speed of 52.6 m/s is climbing upward at an angle of 52° with respect to the horizontal. When the plane's altitude is 760 m, the pilot releases a package.

(a) Calculate the distance along the ground, measured from a point directly beneath the point of release, to where the package hits the earth.
m

(b) Relative to the ground determine the angle of the velocity vector of the package just before impact.

° clockwise from the positive x axis

A bird watcher meanders through the woods, walking 0.30 km due east, 0.70 km due south, and 2.10 km in a direction 38.0° north of west. The time required for this trip is 2.00 h.

(a) Determine the magnitude and direction (relative to due west) of the bird watcher's displacement. Use kilometers and hours for distance and time, respectively.

(b) Determine the magnitude and direction (relative to due west) of the bird watcher's average velocity.

Two point charges lie on the x axis. A charge of + 2.60 pC is at the origin, and a charge of − 4.60 pC is at x=−10.0cm. What third charge should be placed at x=+26cm so that the total electric field at x=+13.0cm is zero?

-Why can't we be certain that the Andromeda Galaxy exists today?

-How do sound and light waves differ?

-What is the frequency of a radio wave that has a wavelength of λ = 100 m?

-Which of these is the same for all forms of electromagnetic (EM) radiation in a vacuum (i.e., empty space)?

wavelength, frequency, velocity, photon energy

-Which of these is emitted when an electron falls from a higher to lower orbital?

another electron, a positron, a neutrino, a photon

Infinite plane sheets of charge lie in z = 0, z = 2, and z = 4 planes with uniform surface charge densities ps1, ps2, ps3 respectively. Given that the resulting electric field intensities at the points (3, 5, 1), (1, -2, 3), and (3, 4, 5) are 0az, 6az and 4az V/m respectively, find ps1, ps2, ps3 and electric field vector at point (-2,1,-6).

What happens to the total current through a parallel circuit as more resistors are added in parallel?

How, approximately, is the total voltage across a power source in a multi resistors connected in parallel related to the voltage across the individual resistors?

An electron and a proton, starting from rest, are accelerated through an electric potential difference of the same magnitude. In the process, the electron acquires a speed ve, while the proton acquires a speed vp. Find the ratio ve/vp.

Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of -0.3675 N when separated by 50 cm, center-to-center. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other with an electrostatic force of 0.3129 N. What were the initial charges on the spheres? Since one is negative and you cannot tell which is positive or negative, there are two solutions. Take the absolute value of the charges and enter the smaller value here.

1. Were the coils being attracted or repelled from one another? How can you tell?

2. If the two coils of wire the apparatus were unwound, straightened and aligned parallel, how long would the parallel wires be? Would this arrangement be practical?

What is an example of a baryon that isn't a proton or a neutron?

• What can be studied with an infrared telescope? Why must they be kept cool?
• What can be studied with higher energy X-ray or gamma ray telescopes?
• Why is it useful to use several telescopes that each study a different part of the electromagnetic spectrum on a single object?

Two stationary positive point charges, charge 1 of magnitude 3.85 nC and charge 2 of magnitude 2.00 nC , are separated by a distance of 39.0 cm . An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two charges. What is the speed vfinal of the electron when it is 10.0 cm from charge 1?

A simple pendulum oscillates with frequency f.

(a) What is its frequency if the entire pendulum accelerates at 2/3g upward?
_____________ f

(b) What is its frequency if accelerates at 0.666666666666667g downward?
_____________ f

How did Einstein expand the light quantum theory in 1917?

Calculate the specific heat of a metal (in calories/gram-degree C) from the following data. A container made of the metal has a mass of 3.10 kg and contains 11.1 kg of water. A 1.10 kg piece of the same metal, initially at a temperature of 140 degrees C, is placed in the water. The container and water initially have a temperature of 15 degrees C, and the final temperature of the entire system is 18 degrees C.