161.Professor Peters walks directly toward a plane mirror at a speed of 0.25 m/s. Determine the speed of the image relative to him
- A. 0.13 m/s
- B. 0.50 m/s
- C. 0.25 m/s
- D. 0.75 m/s
162.The angle of incidence in a denser medium when the angle of refraction in the less dense medium is 90° is called a
- A. Critical angle
- B. Reflected angle
- C. Incident angle
- D. Emergent angle
163.The driving mirror is a
- A. plane mirror
- B. convex mirror
- C. thick plane mirror
- D. iodine
164.The following are types of a converging lens except
- A. biconvex
- B. plano-convex
- C. mini-convex
- D. converging meniscus
165.When the Sun, the earth and the moon are in line during their movement, with the earth being the opaque object and casting its shadow on the moon, we have
- A. Lunar eclipse
- B. Total eclipse
- C. Partial eclipse
- D. Annular eclipse
166.Which of the following instruments could be used in finding angle of elevation of the sun?
- A. Periscope
- B. Telescope
- C. Kaleidoscope
- D. Sextant
167.Which of the following optical instruments does not depend on the use of plane mirrors?
- A. Kaleidoscope
- B. Simple microscope
- C. Sextant
- D. Simple periscope
168.Which of the following statements supports the assumption that light travels in straight lines?
- A. light can be diffracted
- B. light can be reflected
- C. a source of light produces interferences patterns on a suitably placed screen
- D. a source of light produces distinct shadows of opaque objects
169.Which of the following is correct about nuclear fission? It is:
- A. the splitting of a heavy nucleus into two or more lighter particles
- B. an agent used to slow down neutrons in a controlled atomic chain reaction
- C. combing light atomic nuclei to form heavy
- D. the spontaneous disintegration occurring in the nucleus of certain atoms
170.A light energy E falls on a metal and the electrons with a maximum kinetic energy of 0.2eV are ejected. If the work function of the metal is 0.3eV, what is the value of E?
- A. 0.10eV
- B. 0.06eV
- C. 0.50eV
- D. 1.50eV
171.A nucleus is unstable if
- A. it has two or more isotopes
- B. its binding energy is not sufficient to hold nuclear particles together
- C. it is very light with very low density
- D. it has no significant mass
172.A radioactive substance has a half life of 4 years. If its activity today is 200 dps, its activity in 8 years from today is
- A. 50 dps
- B. 25 dps
- C. 20 dps
- D. 10 dps
173.A substance has a half-life of 3min. After 6min, the count rate was observed to be 400.What was its count rate at zero time?
- A. 2400
- B. 200
- C. 1200
- D. 1600
174.An element and its isotopes differ only in the number of
- A. electrons
- B. neutrons
- C. protons
- D. irons
175.Complete the following sentence: When electrons from a heated filament accelerate through vacuum toward a positive plate,
- A. only an electric field will be produced
- B. only a magnetic field will be produced
- C. electromagnetic waves will be produced
- D. longitudinal waves will be produced
176.Radioactive elements are
- A. chemically reactive elements
- B. noble elements
- C. rare earth elements
- D. elements that spontaneously emit radiation
177.The following radiations are electrically neutral except
- A. α-rays
- B. ϒ-rays
- C. X- rays
- D. neutrons
178.Upon which one of the following parameters does the energy of a photon depend?
- A. mass
- B. polarization
- C. amplitude
- D. frequency
179.Which of the following is NOT true about cathode ray?
- A. It moves in a straight line
- B. It causes fluorescence
- C. It possesses a negative charge
- D. It can produce -particles
180.Who proposed the planetary model of the nucleus?
- A. J. J Thomson
- B. Albert Einstein
- C. Ernest Rutherford
- D. Marie Curie