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The Unit 4 EXAM in this class this semester will be on 

According to Gauss’s Law, what is the relationship between the electric field strength (E) and distance (r) to a point from an infinitely long plane sheet of a charged non-conductor? 

A 400 Ω resistor, a 5000 μF capacitor, a switch, and a 10 V battery are in series in a single circuit loop.  The capacitor is initially uncharged at t = 0.  What will be the charge on the capacitor after 4 seconds?

White light is spread out into spectral hues by a diffraction grating.  If the grating has 2000 lines/cm, at what angle will red light (λ = 640 nm) appear in first order?

A positive charge is moving north through a magnetic field pointed vertically upwards.  What direction will the positive charge feel a force?

What would be the angle in water (n=1.33) if light enters from air at 20°?

A 1100 W hair dryer (R1) and a 1600 W space heater (R2) in parallel are plugged into a 120 V outlet.  What is the resistance of hair dryer?

A concave mirror has a focal length of 20 cm.  How far in front of the mirror should an object be placed if a real, same-size image is desired?

A 30 cm long solenoid with a cross sectional radius of 0.75 cm has 125 turns of wire.  The solenoid is connected in series to a switch, a 9 V battery, and a 10 Ω resistor.  The switch is initially open and then is closed.  What is the rate of change in current when the potential difference across the resistor is 3 V?

A square loop of wire of side 0.5 meter and resistance 0.01 Ω is located in a uniform magnetic field of intensity 0.4 T directed out of the page as shown below. The magnitude of the field is decreased to zero at a constant rate in 2 seconds. As the field is decreased, what are the magnitude and direction of the current in the loop?