The correct sequence of energy transformation in the operation of an x-ray tube is i. X-rays ii. Kinetic energy of thermo electrons iii. Potential energy of the target atoms iv. Heat energy of the emitted electrons
- A. iv, iii, ii, i
- B. ii, iv, iii, i
- C. iv, ii, iii, i
- D. iii, iv, ii, i
In a nuclear reactor, chain reactions result from the release of
- A. electrons
- B. photons
- C. neutrons
- D. protons
The number of protons in an element increased by one after a radioactive decay. The element must have decay by emitting
- A. a beta particle
- B. an alpha particle
- C. a gamma ray
- D. a neutron
If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer
- A. an explosion is observed
- B. the rainbow colours are seen
- C. an emission spectrum is observed
- D. dark lines are observed
Which of the following electromagnetic wave can be detected by its heating effect?
- A. ultraviolet radiation
- B. x-rays
- C. gamma rays
- D. infrared radiation
Five 80-W and three 100W are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamp. [1 unit = 1 kWh]
- A. N280.00
- B. N28.00
- C. N7.20
- D. N1.44
A bulb marked 240V, 40W is used for 30 minutes. Calculate the heat generated
- A. 320J
- B. 400J
- C. 10800J
- D. 72000J
Which of the following operations does not represent an action of a force field?
- A. falling of a mango fruit from the tree
- B. picking of nails using a bar magnet
- C. repulsion of two like charges
- D. pushing of a wheel-barrow on a level gound
Which of the following components is used for storing electric charges?
- A. inductor
- B. resistor
- C. capacitor
- D. electrometer
Which of the following statements is correct about resonance? Resonance occurs when a body
- A. vibrates with its natural frequency
- B. is forced to vibrate on its own natural frequency by another body at the same vibration
- C. vibrates at the frquency of the body causing the vibration
- D. vibrates with an irregular frequency
A dry plastic comb used in combing hair was found to attract pieces of paper and dust. The most probable explanation for this phenomenon is that the comb has been given
- A. magnetization by induction
- B. electric charges by induction
- C. electric charges by conduction
- D. electric charges by friction
Which of the following statements about sound wave is not correct? Sound waves can be
- A. reflected
- B. refracted
- C. diffracted
- D. polarized
A sounding tuning fork is brought near the open end of a pipe containing air and the loudness of the sound is observed to increase. This observation is due to
- A. an echo
- B. resonance
- C. interference
- D. reverbration
Which of the following factors can affect the speed of sound in air? i. The temperature of the surrounding ii. The direction of the wind iii. The pitch of the sound.
- A. i and ii only
- B. ii and iii only
- C. i and iii only
- D. i, ii and iii
A rectangular glass prism of thickness d and absolute refractive index n is placed on a point object which is viewed vertically downward from above the prism. Which of the following expressions correctly defines the apparent upward displacement of the object?
- A. \(\frac{d}{n}\)
- B. dn
- C. \(\frac{d}{n - 2}\)
- D. \(\frac{d(n - 1)}{n}\)
When an object is placed at the centre of curvature of a concave mirror, its image is formed at
- A. the focus
- B. infinity
- C. the centre of curvature
- D. a distance twice the radius of curvature
In which of the following piece of apparatus is the radius of curvature equal to twice the focal length?
- A. converging lens
- B. diverging lens
- C. converging mirror
- D. parabolic mirror
An object is placed 10cm in front of a plane mirror. If it is moved 8cm away father away from the mirror, determine the distance of the final image from the mirror
- A. 2cm
- B. 9cm
- C. 16cm
- D. 18cm
Which of the following phenomena is not a direct consequence of rectilinear propagation of light?
- A. lunar and solar eclipses
- B. images of objects in a pin hole camera
- C. diffraction of light
- D. shadows of opaque object
The distance between two points P and Q, along a wave is 0.05m. If the wave length of the wave is 0.10m, determine the phase angle between P and Q in radians
- A. 0.1\(\pi\)
- B. \(\pi\)
- C. 2\(\pi\)
- D. 10\(\pi\)
Which of the following wave is electromagnetic?
- A. x-rays
- B. sound waves
- C. water waves
- D. tidal waves