Electricity and Magnetism Answers

a proton moving horizontally at 3.5x10^4 m/s enters a uniform magnetic field of 0.075 t directed upward at 30°with the horizontal. find the magnitude of the magnetic force acting on the proton

7. Using the formula at the beginning of this lesson, calculate the wavelength of a signal from KPhET 98.7. Remember that FM stations transmit in the Megahertz range. This means that KPhET is transmitting a frequency of 9.87 x107 hz. What is the wavelength of the signal from this radio station?

8. My favorite radio station is NPR, which transmits a signal that is has a wavelength of 3.38 m. What is the frequency of this signal? Remember, light speed is 3 x108 m/s.

9. AM 630 is where I listen to sports. The frequency is 630 khz (or 630,000 hz). What is the wavelength?

10. Pick your favorite radio station, or one your friends listen to. What is its frequency and wavelength?

The force between a 100 kg man and the Earth is 980 N. How close must two protons (1.6 X 10^-19 C) be to generate the same force?

Two electrons are 10^-5 m apart. One electron is fixed on its position. The other, originally at rest, is released. How fast is the free electron moving when it is 10^−3 m from the fixed charge? Apply conservation of energy.

A positive and negative charge, each of magnitude 3.7 * 10 ^ - 6 * C are separated by a distance of 25 cm. Find the force on each of the particles .

Two electrons in an atom are separated by 1.5 * 10 ^ - 10 m , the typical size of an atom. What is the electron forces between them?

Four point charges are positioned as such: A(0,1), B(2,1), C(0,0), D(2,0). Charge A = -3 microcoulombs, Charge B = 3 microcoulombs, C = 2 microcoulombs, and D = -2 microcoulombs. What is the net electric field experienced at the origin.

11– 20. A hydrogen atom consists of a single proton and a single

electron. The proton has a charge of +e and the

electron has −e. In the “ground state” of the atom, the electron orbits

the proton at most probable distance of

7.48 × 10−11 m (as shown in the figure below). Calculate the electric

force on the electron due to the proton?

Three capacitors of capacitances C1 = 15 μF, C2 = 30 μF, and C3 = 45μF were connected in series to a potential difference V. Find the equivalent capacitance of the three capacitors.

Determine the capacitance of a spherical air-filled capacitor of radius, 𝑅_1 = 2.5 c𝑚 and 𝑅_2= 0.45 d𝑚.