Household wiring often uses 2.0 mm diameter copper wires. The wires can get rather long as they snake through the walls from the fuse box to the farthest corners of your house. What is the potential difference across a 18 m long, 2.0 mm diameter copper wire carrying an 7.0 A current?  (Resistivity of copper = 1.7 x 10-8 

What potential difference is needed to accelerate a He+ ion (charge +e, mass 4 u) from rest to a speed of 5.0 x 105 m/s? (mass of a proton = 1.67 x 10-27 kg, charge of electron = 1.6 x 10-19 C)

What is the resistance of the 0.640 mm diameter, 5.20 cm long lead from a mechanical pencil? Pencil “lead” is actually carbon. (Resistivity of carbon = 3.5 x 10-5 

A 3.00 

The electric potential along the x-axis is V = 100e-2x V, where x is in meters. a) What is the Ex at x = 1.0 m? b) What is the Ex at x = 2.4 m?

The magnetic field in the figure is decreasing at the rate 0.25 T/s.  (e = 1.60 x10-19 C, mproton = 1.67×10-27 kg) a) What is the magnitude of the acceleration of a proton at rest at point a? What is the direction of acceleration of point a? b) What is the magnitude of the acceleration of a proton at rest at point d? What is the direction of acceleration of point d?

a) What is the magnetic field amplitude of an electromagnetic wave whose electric field amplitude is 90 V/m? (2 points) b) What is the intensity of the wave? (3 points)  

The electric potential along the x-axis is V = 100e-2x V, where x is in meters. a) What is the Ex at x = 1.0 m? b) What is the Ex at x = 2.2 m?

The magnetic field in the figure is decreasing at the rate 0.80 T/s.  (e = 1.60 x10-19 C, mproton = 1.67×10-27 kg) a) What is the magnitude of the acceleration of a proton at rest at point a? What is the direction of acceleration of point a? b) What is the magnitude of the acceleration of a proton at rest at point d? What is the direction of acceleration of point d?

For a science project, you would like to horizontally suspend an 8.5 by 11 inch sheet of black paper in a vertical beam of light whose dimensions exactly match the paper. If the mass of the sheet is 1.1 g, what light intensity will you need? (1 in = 2.54 cm)