1999 Physics Olympiad Screening Test (Part 2) Printer Friendly Version
21. Which of the following wave properties cannot be demonstrated by all kinds of waves?
22. A source when at rest in a medium produces waves with a velocity v and a wavelength of . If the source is set in motion to the left with a velocity vs what would be the length of the wavelengths produced directly in front of the source?
23. A beam of light strikes one mirror of a pair of right angle mirrors at an angle of incidence of 45o as shown in the diagram.

If the right angle mirror assembly is rotated such that the angle of incidence is now 60o, what will happen to the angle of the beam that emerges from the right angle mirror assembly?

24. What would be the total current being supplied by the battery in the circuit shown?
25. Consider a simple circuit containing a battery and three light bulbs. Bulb A is wired in parallel with bulb B and this combination is wired in series with bulb C. What would happen to the brightness of the other two bulbs if bulb A were to burn out?

26. A coil of wire is moved vertically at a constant velocity through a horizontal magnetic field. Assume the plane of the coil is perpendicular to the magnetic field. Which of the following graphs would best represent the electric current induced in the coil if it started somewhat above the magnetic field and ended equally as far below the magnetic field?

27. Three metal spheres A, B, and C are mounted on insulating stands. The spheres are touching one another, as shown in the diagram.

A strong positively charged object is brought near sphere A and a strong negative charge is brought near sphere C. While the charged objects remain near spheres A and C, sphere B is removed by means of its insulating stand. After the charged objects are removed, sphere B is first touched to sphere A and then to sphere C. The resulting charge on B would be:

28. Which of the following graphs would best represent the electric field of a hollow Van de Graff sphere as a function of distance from its center when it is charged to a potential of 400,000 volts?

29. A mass spectrograph separates ions by weight using simple concepts from physics. Charged ions are given a specific kinetic energy by accelerating them through a potential difference. The ions then move through a perpendicular magnetic field where they are deflected into circular paths with differing radii. How would the radius of a singularly ionized common helium atom 4 2He+1 compare to the radius of a doubly ionized common oxygen atom 16 8O+2 if they were accelerated through the same potential difference and were deflected by the same magnetic field?

30. A bar magnet is thrust into a coil of wire as indicated in the diagram below.

Which of the following statements concerning this experiment is correct?