# Physics 2

What is the resonant frequency of sound when you blow across an empty soda bottle that is 15 cm tall?

Two point charges, q$_1$ = 6Q and q$_2$ = -2Q, are separated by a distance, d. The attractive force between these two particles is 20 N. If the distanced is halved, so d$_2$ = d/2, what is the new force between the particles?

In the figure below, A = 3 cm, B = 1 cm, q$_1$ = +15 nC, q$_2$ = -5 nC, and q$_3$ is -10 nC. Find the magnitude and direction of the net electrostatic force on q$_3$

A proton ( 1.6 x 10$^{-19}$ C ) is placed 2.19 x 10$^{-6}$ m from point A. Find the electric field at point A. Imagine a proton is put at point A. Find the force that acts on the proton.

Two parallel charged plates, one with a surface charge density of $\eta_1$ = 40 $\frac{nC}{m^2}$ and another, $\eta_2$ = -60 $\frac{nC}{m^2}$. Find the total electric field between the plates. (note this is not a capacitor)

The electron gun in a television tube is used to accelerate electrons from rest to 3.0 x 10$^7$ m/s within a distance of 2.0 cm. What electric field is required? Should the electric field be in the same or opposite direction of the electrons motion?

The figure below shows a single dipole of charges $\pm$5 nC, with a distance s = 0.002 m between the poles. Point A is a distance, d = 0.1 m, and is perpendicular to the dipole. Point B is a vertical distance, d = 0.1 m, and is parallel to the dipole. Find the electric field at points A and B.

Two dipoles are placed a distance, d = 0.05 m, from the point A (labeled in red). The distance between dipoles is s = 0.01 m. Each dipole consists of a positive and negative charge of $\pm$2 nC. Find the electric field at point A.

Two concentric loops are shown below, with a distance between them Y = 0.4 m, a radius Z = 0.1 m. The loop on the left has a charge of +9 nC and the loop on the right has a charge of -9 nC. Find the electric field at point X, which is directly in the middle of the loops.

Given the 3 dimensional electric field, $\vec{E}$ = 200 $\frac{N}{C}$ $\hat{i}$ + 300 $\frac{N}{C}$ $\hat{j}$ + 400 $\frac{N}{C}$ $\hat{k}$ , and an area vector $\vec{A}$ = 0.2 m$^2$ $\hat{i}$ + 0.3 m$^2$ $\hat{j}$, find the electric flux. (this is a calculus based physics problem)

A sphere carries a charge of +2 nC. Point A is X = 0.02 m to the direct right of the sphere, and point B is Y = 0.06 m to the right of the sphere. Find the electrostatic potential difference from A to B. (the solution involves calculus)

A very long thin wire carries a line charge density, $\lambda$ = 361.0 $\frac{nC}{m}$. Find the electric potential difference between points 3.0 m and 6.0 m on a perpendicular radius to the axis of the wire, provided the perpendicular radius is not near either end of the wire. (this problem requires calculus)

A circuit has 2 capacitors in parallel, A = 20 $\mu$F, B = 10 $\mu$F, with a 10 V battery. Find the potential difference across each capacitor, and the charge of each capacitor.

What are the voltage drops across each capacitor? How much energy will capacitor C store?

The battery is 12 V

A circuit has the following R = 20 $\Omega$, C = 25 $\mu$F, $\Delta{V}_C$ = 10 V.

How long will it take for the charge to drop to one third its original value?

As a steel guitar string vibrates, the component of the magnetic field perpendicular to the area of a pickup coil nearby is given by B(t) = 50 mT + (3.20 mT) Sin (1046$\cdot\pi$t). The circular pickup coil has 30 turns, a radius of 2.70 mm, and a resistance of 0.10 $\Omega$. What is the magnitude of the maximum current induced in the coil?

A rectangular wire loop rests in a magnetic field as shown. Points Y and Z are grasped and pulled tight so that the area of the loop becomes zero. Determine the direction of the current through the resistor.

A conductive ring is falling through a magnetic field as shown below.

A. Sketch the direction of the induced current at each location

B. Where is the induced current the greatest?