An image which can be formed on a screen is said to be
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1991
Calculate the refractive index of the material of the glass block shown in the diagram if YZ = 4cm
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1991
The sound from a bell in an enclosed jar gradually faints away while the jar is being evacuated. Which of the following explains this observation?
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1991
Which of the following remains unchanged as light travels from one medium to the other? i. speed. ii. wavelength. iii. frequency.
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1991
Which of the following is not a mechanical wave?
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1991
If the frequency of the e.m.f. source in the a.c. circuit illustrated above is \(\frac{500}{\pi}\)Hz. What is the reactance of the inductor?Inductance (L) = 0.9H
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1991
A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field b in the direction of the field. The force on the particle is
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1991
Which of the following statements is true of the diagram shown above?
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1991
Using the data in the circuit illustrated above, calculate the value of R
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1991
Which of the following is stored by dry Leclanche cell?
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1991
In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most?
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1991
Two capacitors C1 and C2 are connected as shown in the diagram. The capacitance C2 is twice C1 when the key is opened the energy stored up in C1 is W. If the key is later closed and the system is allowed to attain electr…
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1991
Two objects of masses 80kg and 50kg are separated by a distance of 0.2m. If the gravitational constant is 6.6 x 10-11Nm kg, calculate the gravitational attraction between them.
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1991
An induction coil is generally used to
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1991
The diagram above shows a current carrying wire between the poles of a magnet. In which direction would the wire tend to move?
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1991
A house is supplied with a 240V a.c mains. To operate a door bell rated at 8v, a transformer is used if the number of turns in the primary coil of the transformer is 900. calculate the number of turns in the secondary co…
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1991
In the circuit above R is a resistor whose resistance increases with increases with increase in temperature L1 and L2 are identical lamps. If the temperature of R increases
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1991
A 90W immersion heater is used to supply energy for 5 minutes. The energy supplied is used to completely melt 160g of a solid at its melting point. Calculate the specific latent heat of the solid.
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1991
When a metal surface is irradiated, photoelectrons may be ejected from the metal. The kinetic energy of the ejected electrons depends on the