Physics Past Questions And Answers
Which of the following factors decreases the rate of evaporation of a liquid?
- A. increase in pressure over the liquid
- B. lowering the boiling point
- C. decreasing in humidity
- D. wind
Which of the following has the shortest wavelength?
- A. Infrared rays
- B. Gamma rays
- C. Ultra violet rays
- D. Radio waves
A body of mass 200g and specific heat capacity 0.4Jg-1k-1 cools from 37oC to 31oC. Calculate the quantity of the heat released by the body.
View Discussion (0)WAEC 2007 OBJ
The derived unit of pressure can be expressed as
- A. kgms-2
- B. kg m-1s-2
- C. kg m-2s-2
- D. kg m-1s2
An object of volume 400cm3 and 2.5gcm-3 is suspended from a spring balance with half its volume immersed in water. Determine the reading on the spring balance. (Density of water = 1gcm-3)
- A. 1200g
- B. 1000g
- C. 800g
- D. 400g
A wheel and axle have radii 80cm and 10cm respectively. If the efficiency of the machine is 0.85, an applied force of 1200N to the wheel will raise a load of
- A. 8.0N
- B. 6.8N
- C. 8160N
- D. 9600N
The resistance in a series R-C circuit is 5Ω. If the impedance of the circuit is 13Ω, calculate the reactance of the capacitor
- A. 65Ω
- B. 18Ω
- C. 16Ω
- D. 12Ω
The magnetic material produced from the chemical combination of metal oxides and has a very high resistance to electric current is called
- A. ferrite substance
- B. paramagnetic substance
- C. ferromagnetic substance
- D. diamagnetic substance
Which of the following concepts is a method of heat transfer that does not require a material medium?
- A. Conduction
- B. Diffusion
- C. Convection
- D. Radiation
(a) (i) What is a machine?
(ii) State two uses of gears.
(iii) Define the velocity ratio for a pair of gear wheels.
(iv) How can the mechanical advantage of a gear system be increased?
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The diagram below illustrates the gears system of a bicycle.
(i) Determine its velocity ratio.
(ii) If the bicycle has an efficiency of 90%, calculate the effort required to overcome a load of 70N.
(iii) Why is the calculated effort less than the actual effort required?
View Discussion (0)WAEC 2012 THEORY