Which of the following statements about X-rays is not correct? They
- A. are electromagnetic waves
- B. can be used to study crystal lattice
- C. can destroy living cells
- D. are produced from the nucleus of an atom
In which of the following devices is the principle of photoelectric effect not applicable?
- A. close-circuit television camera
- B. burglar alarm
- C. solar cells
- D. periscope
An atom is normally electrically neutral because the
- A. number of electrons is equal to the number of protons
- B. number of electrons is equal to the number of neutrons
- C. number of protons is equal to the number of neutrons
- D. electrons of the atom are buried deeply in the nucleus
The main function of the mouth piece of a telephone is that it converts sound energy to
- A. mechanical energy
- B. electrical energy
- C. chemical energy
- D. thermal energy
Which of the following statements is not correct?
- A. a magnetic field is a region in which a magnetic force will be detected
- B. a magnetic line of force is a path along which a magnetic fields are scalar quantities it were free
- C. magnetic fields are scalar quantities
- D. neutral point are obtained where the earth's magnetic force is exactly equal and opposite to that due to a magnet
A charge of 1.6 x 10-10C is placed in a uniform electric field of intensity 2.0 x 105 NC-1. calculate the magnitude of the electric force exerted on the change
- A. 3.2 x 105N
- B. 1.8 x 105N
- C. 3.2 x 10-5N
- D. 1.8 x 10-5N
Given that the gravitational constant is G. Newton’s universal law of gravitation states that the force of attraction between two masses M1 and M2 separation by a distance r is
- A. \(Gr^2 M_1M_2\)
- B. \(Gr M_1M_2\)
- C. \(\frac{GM_1 M_2}{r^2}\)
- D. \(\frac{GM_1 M_2}{r}\)
Calculate the energy stored in a 20\(\mu F\) capacitor. If the p.d between the plates is 40V
- A. 3.2 x 10-2J
- B. 1.6 x 10-2J
- C. 8.0 x 10-4J
- D. 4.0 x 10-4J
The quantity of electric charge stored in a capacitor is measured in
- A. farad
- B. ampere
- C. coulomb
- D. volt
Find the cost of running a 60W lamp for 24 hours. If 1kW hr cost 5 naira
- A. 14.4 naira
- B. 12.5 naira
- C. 7.2 naira
- D. 2.0 naira
A car fuse marked 3A operates optimally on a 12V battery, calculate the resistance of the fuse
- A. 36.0\(\Omega\)
- B. 15.0\(\Omega\)
- C. 9.0\(\Omega\)
- D. 4.0\(\Omega\)
Which of following functions is performed by manganese IV oxide in the Lenclanche cell?
- A. control of local action
- B. depolarisation of the cell
- C. regulating current flow in the cell
- D. reduction of the internal resistance of the cell
Charges on a conductor are
- A. evenly distributed over a surface of any shape
- B. concentrate on the inner surface of the conductor
- C. concentrate at the outer flat surface of the conductor
- D. generally concentrated at sharply curved surface
The sound from a vibrating tuning sound is when the tip of its stem is placed on a wooden table than when in air because
- A. the friction between the table and the tuning fork generates additional energy
- B. air molecules obsorb sound wave but wood transmit sound waves
- C. the table increases the frequency of the turning fork
- D. a large mass of air is set into vibration by the table
Which of the following reasons explains why the walls and ceilings of a standard concert hall are usually covered with perforated pads? To
- A. increase the intensity of sound waves
- B. increases the loudness of the sound waves
- C. reduce the effect of revibration of sound waves
- D. decreases thr frequency of sound waves
A girl stand 80m away from a tall cliff and blows a whistle. If the speed of sound in air is 330ms-1, how long would it take for her to hear the echo of the sound?
- A. 2.062s
- B. 0.970s
- C. 0.485s
- D. 0.242s
A magnified and virtual image of a near object is produced by
- A. prism binoculas
- B. astronomical telescope
- C. periscope
- D. simple microscope
During a thunderstorm, lightning and thunder occurred simultaneously in the atmosphere. An observer on the earth surface’s sees the lightning flash shortly before hearing the thunder. This is because the
- A. atmospheric pressure is higher at the surface than at the higher altitudes
- B. speed of sound is less than that of light
- C. temperature of the atmosphere decreases with altitude
- D. atmospheric density decreases with altitude
A man 1.8m tall stands 3m away from a pin hole camera. If the distance between the pin hole and the screen of the camera is 0.3m. Calculate the height of the image of the man produced by the camera
- A. 0.18m
- B. 0.50m
- C. 1.62m
- D. 18.00m
The image of an optical pin placed at the principal focus of a concave mirror will be formed
- A. between the principal focus and the pole
- B. at the centre of the curvature
- C. between the principal focus and the centre of curvature
- D. at infinity
A wave travelling from water to glass suffers a change in its speed at the common boundary. Which of the following properties explains this observation?
- A. dispersion
- B. refraction
- C. interference
- D. diffraction