1. Determine the magnitude and direction of the electric field at a point midway between a -6.μC and a +4.5 μC charge at 8.0 cm apart.  Assume no other charges are nearby.

2. Determine the potential at a point 0.60 m from:

a) a +30 μC  point charge:

b) a -30 μC point charge:

3. What is the current if a circuit has a 12-volt battery and a 2 Ohm resistor?  V = IR.

4. The following two questions are based on series and parallel circuits.

a) A 750-Ω and an 1600-Ω resistor are connected in series with a 12-V battery.  What is the voltage across the 1600-Ω resistor?

b) A 750-Ω and an 1600-Ω resistor are connected in parallel with a 12-V battery.  What is the voltage across the 1600-Ω resistor?

5. A wire carrying a steady (dc) 40-A current has a length l = 26 cm between the pole faces of a magnet.  The wire is at an angle θ = 45⁰ to the field.  The magnetic field is approximately uniform at 1.20 T.  We ignore the field beyond the pole pieces,  Determine the magnitude and direction of the force on the wire.

6. An average  of 120 kW of electric power is sent to a small town from a power plant 20 km away.  The transmission lines have a total resistance of 0.6 Ω.  Calculate the power loss if the power is transmitted at the following:

a) 350 V

b) 35,000 V

7. Calculate the wavelength of the following:

a) of a 60-Hz EM wave:

b) of a 93.3-MHz FM radio wave:

c) of a beam of visible red light from a laser at frequency 4.74 x 10¹⁴  Hz^:

8. Calculate the position and the size of the image of a 8.4-cm-high leaf placed 1.20 m from a +70.0-mm-focal point camera lens.

9. Wavelengths from double-slit interference.  White light passes through two slits 0.50 mm apart, and an interference pattern is observed in a screen 2.5 mm away.  The first-order fringe resembles a rainbow with violet and red light at opposite ends.  The violet light is abut 2.0 mm and the red 3.5 mm from the center of the central white fringe.  Estimate the wavelengths from the violet and red light.

10. A Farsighted eye has a near point of 80 cm.  Reading glasses must have what lens power so that a newspaper can be read at a distance of 25 cm?  Assume the lens is very close to the eye.