A lamp marked 100W, 250V is lit for 10 hours. If it operates normally and 1KWh of electrical energy costs 2k, what is the cost of lighting the lamp?
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1994
A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field of strength B in the direction of the field. The force on the particle is
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1994
A car fuse is marked 15A and operates normally on a 12V battery. Calculate the resistance of the fuse wire
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1994
Which of the following substances is not an insulator?
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1994
Beta particles are
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1994
A body accelerates uniformly from rest at \(2ms^{-2}\). Calculate the velocity after traveling 9m
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1994
A ball is dropped from a height of 45m above the ground. Calculate the velocity of the ball just before it strikes the ground. (Neglect air resistance and take g as \(10ms^{-2}\)
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1994
A note of frequency of 2000Hz has a velocity of \(400ms^{-1}\). What is the wavelength of the note?
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1994
The wave function of a metal is 8.0 x \(10^{-19}\)J. Calculate the wavelength of its threshold frequency. (Speed of light in a vacuum = 3 x \(10^8ms^{-1}, Planck's constant = 6.6 \times 10^{-34}\)Js)
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1994
The pressure of air in a tire is \(22.5Nm^{-2}\) at 27°C. If the air in the tyre heats up to 47°C, calculate the new pressure of the air, assuming that no air leaks out and that the change in volume of the air can be neg…
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1994
\(500cm^{-3}\) of a gas is collected at 0°C and at a pressure of 72cm of mercury. What is the volume of the the gas at the same temperature and at a pressure of 76cm of the same mercury?
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1994
An electric kettle rated 1500W boils away 0.3kg of a liquid at its boiling point every 300s. Calculate the specific latent heat of the vaporisation of the liquid
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1994
500g of water is heated so that its temperature rises from 30°C to 72°C in 7 minutes. calculate the supplied per minute. (Specific heat capacity of water is 4200J\(kg^{-1}K^{-1}\)
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1994
A metal rod of length 40cm at 20°C is heated to a temperature of 45°C. If the new length of the rod is 40.05cm. Calculate its linear expansitivity
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1994
The density of water is 1g\(cm^3\) while that of ice is 0.9\(cm^3\), calculate the volume change when 90g of ice is completely melted
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1994
The density of a body is \(5\times10^3kgm{^-3}\) and it weighs 1N in air. Calculate the apparent weight of the body when totally immersed in water. (Density of water =\(10^3kgm{-3}, g= 10ms^{-2}
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1994
A light wave travels from air into a medium of refractive index 1.54. If the wavelength of the light in air is \(5.9\times10^{-7}\)m, calculate its wavelength in the medium
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1994
Calculate the time taken to heat 2kg of water from 50°C to 100°C in an electric kettle taking 5A, from a 210V supply. (Specific heat capacity of water = 4200\(kg^{-1}K{-1}\)
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1994
(a) State the laws of electromagnetic induction(b) Explain how one of the laws illustrates the principle of conservation of energy(c)(i) Draw a labelled diagram of a simple d.c. electric motor and explain how it works.(i…
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1994
(a) Explain what is meant by a magnetic field(b)(i) Describe an experiment to show that a magnetic field exists around a straight wire carrying current(ii) Draw a labelled diagram showing the pattern and direction of the…