1. A particular sample of a semiconductor consists of silicon doped with the group V element, arsenic. Which of the following properties would apply to this sample?
A. It would have more protons than electrons.
B. It would have more electrons than protons.
C. It would have the same number of electrons and protons.
D. It would have the same number of electrons and holes.
2. The electrons in Thomson’s cathode ray experiment passed undeflected through an electric and magnetic field. Which of the following statements describes the fields?
A. The electric field was equal and opposite to the magnetic field.
B. The electric field produced a greater force on the cathode rays than the magnetic field.
C. The magnetic field produced a greater force on the cathode rays than the electric field.
D. The electric field and magnetic field were at right angles to each other.
3. Hertz was the first to produce radio waves and measure their velocity. What method did he use to determine their velocity?
A. He measured the time it took them to travel a known distance.
B. He measured their wavelength by studying interference patterns then used the formula; v = fl
C. He measured their wavelength by studying resonance in closed pipes, then used the formula; v = fl
D. He examined the interference patterns formed between light waves and radio waves.
4. William Henry Bragg and William Lawrence Bragg won a Nobel Prize for using diffraction methods to study the structure of crystals. What type of diffraction did they use?
A. X-ray
B. Light
C. Electron
D. Radio wave
5. It is found that when an ultra-violet lamp shines onto a metal plate, the plate emits electrons. What will happen if a second ultra-violet lamp is placed next to the first, so that two ultra-violet lamps shine onto the metal plate?
A. The number of electrons emitted per unit time will increase.
B. The kinetic energy of the emitted electrons will increase.
C. Both the number of electrons per unit time and their kinetic energy will increase.
D. There will be no change in either the number of electrons emitted per unit time or their kinetic energy.
6. What is the main reason that silicon is preferred to germanium to make solid-state electronic devices?
A. Silicon is easier to purify than germanium.
B. Silicon is more abundant than germanium.
C. Silicon devices can operate at higher temperatures than germanium devices.
D. Silicon is a semiconductor whereas germanium is not.
7. When a magnet is placed on a superconductor that has been cooled below its critical temperature, the magnet will levitate, i.e. remain suspended in mid-air above the superconductor. What is the reason for this?
A. The superconductor excludes the magnetic field of the magnet.
B. The superconductor will produce a magnetic field of the same polarity as the magnet.
C. The superconductor will produce a magnetic field of opposite polarity to the magnet.
D. The resistance of the superconductor has dropped to zero.
8. In 1957 Bardeen, Cooper and Schrieffer put forward an explanation of superconductivity. This is now known as the BCS theory of superconductivity. What does the BCS theory of superconductivity propose?
A. The attraction of the electron to the crystal lattice causes it to move faster.
B. An electron changes its charge to positive so that it can attract another electron to form a Cooper pair.
C. The crystal lattice will not vibrate below the critical temperature and this stops resistance to electron flow.
D. Electrons cause the crystal lattice to distort and emit energy that allows electrons to pair up and flow unimpeded.
9. How many photons will be emitted from a 60 watt monochromatic light of wavelength 500nm shining for 1 minute?
A. 1.5 x 1017
B. 9 x 1018
C. 1.5 x 1020
D. 9 x 1021
10. Protons and neutrons are fermions and also baryons. Which of the following describes protons and neutrons?
A. Electrons are kept in circular motion around the nucleus by the electrostatic attraction between the electron and the nucleus.
B. Electrons orbit the nucleus in standing wave patterns consisting of a whole number of wavelengths.
C. Electrons drop from a high energy level to a lower energy level and emit a photon of definite frequency.
D. No two electrons in the same atom can have exactly the same orbit.