How long will it take to heat 3 kg of water from 28oC to 88oC in an electric taking a current of 6 A from an e.m.f. source of 220V?
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1990
A rectangular coil of wire can rotate in a magnetic field. The ends of the coil are soldered to the two halves of a split ring. Two carbon brushes are made to press lightly against the split ring and when these are conne…
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1990
Water does not drip through an open umbrella of silk material unless the inside of the umbrella is touched. Which of the following phenomena is responsible for this?
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1990
Which of the following statements about the atom is/are correct? I. Energy is needed to remove electrons from an atom II. Particles in the nucleus of an atom are bound together by strong forces. III. A large amount of en…
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1990
When the pressure of the gas in a discharge tube is gradually lowered. I. there is a violet glow in the tube II. the glow in the tube splits into bands which get further apart. III, the glow and the bands eventually disa…
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1990
What is the difference between a crystalline and an amorphous solid? A crystalline solid
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1990
Which of the following is not crystal?
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1990
Viscosity in a liquid does not depend on the
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1990
A metal is illuminated with a radiation of energy 6.88eV If the kinetic energy of the emitted electrons is 1.5OeV, calculate the work function of the metal.
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1990
If the temperature of water is gradually increased from 0o to 4oC, the density of the water within this range
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1990
A radioactive substance has a half-life of 20 hours. What traction of the original radioactive nuclide will remain after 80 hours?
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1990
A simple pendulum makes 50 oscillations in one minutes. Determine its period of oscillation
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1990
The nucleon number and the proton number of a neutral atom of an element are 238 and 92 respectively. What is the number of neutrons in the atom?
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1990
A cell of e.m.f. 1.5V and internal resistance of 2.5Ω is connected in series with an ammeter of resistance 0.5W and a resistor of resistance of 7.0Ω. Calculate the current in the circuit.
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1990
(a) Explain the terms nuclear fission and nuclear fusion.(b) State two advantages of fusion over fission and explain briefly why, in spite of these advantages, fusion is not normally used for the generation of power.(c)…
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1990
(a) Define the capacitance of a capacitor.(b) State three factors on which the capacitance of a parallel plate capacitor depends.(c) Derive a formula for the energy W stored in a charged capacitor of capacitance C carryi…
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1990
(a) Define the boiling point of a liquid.(b) Describe an experiment to determine the boiling point of small quantity of a liquid.(c) A piece of copper of mass 300 g at a temperature of 950°C is quickly transferred to a v…
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1990
(a) Using a suitable diagram, explain how the following can be obtained from a velocity-time graph (i) acceleration; (ii) retardation; (iii) total distance covered.(b) Show that the displacement of a body moving with uni…