The change in mass of fuel during a nuclear reaction is 2.0 x 10-27 kg. Calculate the amount of energy released. (Speed of light = 2.0 x 108ms-1)
- A. 1.8 x 10-10J
- B. 9.0 x 10-11J
- C. 6.0 x 10-19J
- D. 1.2 x 10-45J
Uranium-234 disintegrated to form Thorium-230 by emitting
- A. alpha particles
- B. gamma rays
- C. beta negative rays
- D. beta positive rays
Which of the following properties is not applicable to X-rays? They
- A. travel in straight lines
- B. travel with the speed of light
- C. are deflected by magnetic field
- D. affect photographic films
For photoelectric emission, the threshold frequency is the
- A. maximum frequency of incident radiation that will eject elecrons
- B. minimum fraquency of incident radiation required to eject elecrons
- C. frequency which results in the emission of the greater number of electrons
- D. fraquency whch impacts greatest kinetic energy to emitte electrons
Which of the following practices will lead to losses in electrical power transmission?
- A. using transmission cables of large diameter
- B. transmitting at high voltage and low current
- C. transmitting at relatively low voltage and high current
- D. using a set-up transformer at the production end
A wire of length 30cm is moved with a speed of 2ms-1 at right angles to a magnetic field of flux density 0.4T. calculate the emf induced in the wire
- A. 0.15V
- B. 0.24V
- C. 2.70V
- D. 24.00V
The resistivity, \(\mathit{P}\), of a material of length l, cross-sectional area A, resistance R, is given by the equation
- A. \(\mathit{P} = \frac{RA}{l}\)
- B. \(\mathit{P} = \frac{l}{RA}\)
- C. \(\mathit{P} = \frac{Rl}{A}\)
- D. \(\mathit{P} = \frac{R}{Al}\)
An ammeter with a full scale deflection of 10mA has an internal resistance 0.5\(\Omega\). calculate the resistance of the shunt required to adapt it to read up to 3A
- A. 0.0167\(\Omega\)
- B. 0.0130\(\Omega\)
- C. 0.0250\(\Omega\)
- D. 0.1000\(\Omega\)
Which of the following substances does not conduct electricity?
- A. graphite
- B. glass
- C. sulphuric acid
- D. table salt solution
When the pointed end of an uncharged optical pin is brought near the cap cf a positively charged electroscope, it is observed that the gold
- A. collapse slowly
- B. vibrate
- C. are not affected
- D. diverge rapidly
The capacitance of a parallel-plate capacitor
- A. decreases when the seperation between the plate decreases
- B. increases when the optential difference between the plates is increased
- C. is greater without a dielectric material between the plates than with a dielectric
- D. is greater with a dielectric between the plates than without a dielectric.
The correct relationship between “G” and “g” in a gravitational field is given by the equation (Where the symbols have their usual meanings)
- A. g = \(\frac{GM}{R}\)
- B. g = \(\frac{GM}{R^2}\)
- C. g = \(\frac{GM^2}{R}\)
- D. g = \(\frac{GM^2}{R^2}\)
Which of the following statements about the electromagnetic waves is correct?
- A. radio waves have longer frequencies than x-rays
- B. x-rays have the longest wavelength
- C. some of the waves travel at 3.0 x 108ms-1
- D. white light occupies a region beyond ultraviolet rays
The main difference between echo and reverberation is that
- A. reverberation is reflected sound while echo is refracted sound
- B. the time interval between incident sound and reflecte sound is shorter for reverbration
- C. the amplitude of an echo is greater
- D. reverberation is from acoustic speakers while echo comes from clifts
two sound waves have frequencies of 12Hz and 10Hz. Calculate their beats period
- A. 0.5s
- B. 1.0s
- C. 1.2s
- D. 2.0s
The focal length of the eye-piece of an astronomical telescope is f1, while the focal length of the object is f2. Fro normal adjustment, the angular magnification is given by
- A. \(\frac{f_2}{f_1}\)
- B. 1 - \(\frac{f_2}{f_1}\)
- C. \(\frac{f_2}{f_1}\) - 1
- D. \(\frac{f_1}{f_2}\)
Presbyopia is a defect of the eye resulting from
- A. weak ciliary muscles
- B. short eyeball
- C. loss of sphericity of the lens
- D. long eyeball
An object is placed 20.0cm in front of a converging lens of focal length 15.0cm. Calculate its image distance
- A. 1.3cm
- B. 8.6cm
- C. 35.0cm
- D. 60.0cm
The speed of light in a certain medium is V while its speed in a vacuum is C. The absolute refractive index of the medium is
- A. C + V
- B. \(\frac{C}{V}\)
- C. \(\frac{V}{C}\)
- D. C - V
Total internal reflection occurs in an optical prism when light rays
- A. travel from the prism into an optically denser medium
- B. are incident in the prism at an angle greater than the critical angle
- C. are incident normally in the prism
- D. travel from the prism to the air