Physics Past Questions And Answers
The count rate of a radioactive material is 800 count/min. If the half-life of the material is 4 days, what would the count rate be in 16 days later
- A. 200 count / min
- B. 100 count / min
- C. 50 count / min
- D. 25 count / min
In flemings right-hand rule, the thumb, the forefinger and the middle finger if held mutually at right angles represent respectively, the
- A. motion, the field and the induced current
- B. induced current, the motion and the field
- C. field, the induced current and the motion
- D. induced current, the field and the motion
(a) Define the boiling point of a liquid.
(b) With the aid of a sketch diagram, describe an experiment to determine the boiling point of a small quantity of a Iiquid
(c) A piece of copper of mass 300 g at a temperature of 950°C is quickly transferred into a vessel of negligible thermal capacity containing 250 g of water at 25°C. If the final steady temperature of the mixture is 100°C, calculate the mass of water that will boil away. Especific heat capacity of copper = 4.0 x 10\(^2\) J kg\(^{-1}\)K\(^{-1}\) specific heat capacity of water = 4.2 x 10\(^{3}\) J kg\(^{-1}\)K\(^{-1}\) specific latent heat of vaporization of steam = 2.26 x 10\(^6\)J kg\(^{-1}\)
.jpeg)
The mercury column in the barometer at notational atmospheric pressure has a height of?
- A. 0.76 cm at see level
- B. 760 cm at sea level
- C. 7.6 cm at sea level
- D. 76 cm at sea level
Two forces of magnitudes 7N and 3N act at right angles to each other. The angle \(\theta\) between the resultant and the 7N force is given by
- A. cos\(\theta\) = \(\frac{3}{7}\)
- B. sin\(\theta\) = \(\frac{3}{7}\)
- C. tan\(\theta\) = \(\frac{3}{7}\)
- D. cot\(\theta\) = \(\frac{3}{7}\)
the core of a transformer is usually laminated in order to
- A. reduce magnetic leakage
- B. reduce eddy current
- C. prevent vibration of the transformer
- D. make magnetic reversal in the core much easier
Which of the following statements is/are correct? I. Pure water freezes at 0°C under normal pressure ll. Water has its highest density at 4°C. III. The volume at 4°C,
- A. I only
- B. II only
- C. I and II only
- D. I and III only
The theory of electronic conduction in solids, which satisfactorily explains the properties of conductors, insulators and semi-conductor, is?
- A) string theory
- B) particle theory
- C) group theory
- D) band theory
The temperature of a piece of metal of mass 9 g is raised from 10oC to 110oC when it absorbs 108J of heat energy. Determine the specific heat capacity of the metal in J kg-1K-1
- A. 1.2
- B. 12.0
- C. 120.0
- D. 1200.0
A man hears his echo from a nearby hill 2s after he shouted. If the frequency of his voice is 260Hz and the wavelength is 1.29m, how far away is the hill?
- A. 330.0m
- B. 335.4m
- C. 660.0m
- D. 670.8m