22. Waves are produced by two point sources S and S’ vibrating in phase. See the accompanying diagram. X is a point on the second nodal line.

 

 

The path difference SX – S’X is 4.5 cm. The wavelength of the waves is approximately

23. A thin film of thickness t and index of refraction 1.33 coats a glass with index of refraction 1.50 as shown below.

 

Which of the following thicknesses t will not reflect light with wavelength 640 nm in air?

25. A charge is uniformly distributed through a volume of radius a. Which of the graphs below best represents the magnitude of the electric field as a function of distance from the center of the sphere?

 

26. A free electron and a free proton are placed between two oppositely charged parallel plates. Both are closer to the positive plate than the negative plate.

 

 

Which of the following statements is true?

 

27. In the electrical circuit shown below, the current through the 2.0-ohm resistor is 3.0 A.

 

 

The emf of the battery is about

29. Which of the following wiring diagrams could be used to experimentally determine R using Ohm’s Law? Assume an ideal voltmeter and an ideal ammeter.