NECO SSCE - Physics - 2000

A radioactive substance has a half-life of 3 minutes. After 9 minutes, the count rate was observed to be 200. What was the count rate at zero time?

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When a metal is heated to a high temperature, electrons are emitted from its surface. The process is known as

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A solid weights 5.0 N in air, 4.2 N in water and 4.4 N in liquid Y. Calculate the relative density of liquid Y.

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Two 2.0Ω resistors can be combined circuit to give an overall resistance of

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What is the coefficient of static friction between a load of mass 2kg and a horizontal surface, if the limiting frictional force is 10N? (g = 10 ms^-2)

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400g of cold water is added to 200g of water at 70°C. If they are properly mixed and the temperature of the mixture is 300°C. calculate the initial temperature of the cold water. (Neglect the heat absorbed by the container)

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When a lever is in equilibrium, under the action of two or more forces, the algebraic sum of the moments of the forces about the point of support is

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Which of the following statements about evaporation and boiling is FALSE?

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The helium isotope \(^3_2He\)

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The length of a side of a metallic cube at 20° C is 5.0cm. Given that the linear expansively of the metal is 4.0 × 10^-5K^-1, find the volume of the cube at 120° C

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The clinical thermometer differs from other mercury-in-glass thermometers because it has

I. a constriction
II. a wide range
III. a short range
IV. a narrow bore.

Which of the above are correct?

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A gas occupies a certain volume at 27°C. At what temperature will its volume be twice times the original volume assuming that its pressure remains constant?

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The image obtained on the screen of a pin-hole camera becomes less sharply defined when the

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A boy moving with a velocity of 3 ms^-1 is brought to rest by a constant force after travelling 15m. Calculate the retardation.

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A man at the back of a crowd watches a parade by holding a plane mirror just above his head. The parade passes 6 metres behinde his head and the mirror is 0.25m in front of the man. How far does the image in the mirror appear to be from the man?

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The unit of inductance is

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A boy ran a distance of 200m in 24s. His average speed was 8.3ms^-1. Which of the following is correct about the units in which the statements above are expressed?

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A man standing 510m away from a wall sounds a whistle. The echo from the wall reaches him 3s later. Calculate the velocity of sound in air.

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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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The specific heat of a substance in the solid state is C₁; its specific beat in the liquid state is C₂ and its latent heat of fusion is L. If a mass M of the substance is changed from the solid state at temperature T, to the liquid state, also at temperature T, the amount of heat required will be

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The image formed by a converging lens of focal length is of a distance of 2f from the lens. Calculate the lateral magnification produced

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Which of the following is/are TRUE of nuclear fission?

I. A heavy nucleus is split into two nuclei of comparable masses
II. Two light nuclei are joined together to form a heavier nucleus
III. The total mass of the products is less than that of the reactants

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The heat from a fire in a closed room reaches someone far away in the room, mainly by

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The image is a plane mirror is

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The force exerted on a charged body in an electric field depends on

I. the charge on the body
II. the electric field intensity
III. the square of the mass of the body

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A wave travels a distance of 20 cm in 3s. The distance between successive crests of the wave is 4cm. What is the frequency of the wave?

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An element of nuclear number A and proton number Z emits an alpha particle from its nucleus. The nucleon number and the proton number of the new element formed are respectively

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The half-life of a radioactive substance is 2 seconds. Calculate the decay constant.

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Which of the following is NOT part of an a.c generator?

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Which of the following pairs of light rays shows the widest separation in the spectrum of white light?

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A block of a substance X will sink in a liquid V but float liquid Z. Which of the following statements is NOT correct about the densities of the three substances?

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The smallest unit on the sleeve of a micrometer screw gauge is 0.5mm. There are fifty divisions on the thimble of the screw gauge.
What is the smallest length that can be measured with this instrument?

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When electrical power is transmitted over long distances, the voltage is stepped up so that

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I. A scalar quantity has only magnitude
II. A scalar quantity has both magnitude and direction
III. A vector quantity has both magnitude and direction
IV. A vector quantity has only magnitude.

Which of the above statement is/are correct?

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Calculate the peak voltage of a mains supply of r.ms. value 220V.

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An astronomical telescope which is being used to view a very distant object is said to be in normal adjustment if

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Which of the following is used in a nuclear reactor to slow down fast moving neutrons?

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Two forces forming a couple are separated by a distance of 25cm. If one of the forces equals 40N, what is the moment of the couple?

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If the first position of resonance in a resonance tube is 18.0cm from the open end, the distance from the open end to the next position of resonance will be

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In a simple pendulum experiment, a boy observed that the times for 30 oscillations are 70.0s, 72.0s and 67.0s respectively. Calculate the mean period of oscillation of the pendulum.

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An electric bell operated within an evacuated bell jar enables us to infer correctly that

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Which of the following is/areNOT affected by a magnetic field?

I. Alpha particle
II. Cathode rays
III. Neutrons

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To keep a lorry moving at a constant speed v, requires power p, from the engine. The force provided by the engine is

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A piece of stone weights 180 N in air and 150 N in a beaker containing 160 N of methylated spirit. What is the up thrust exerted on the stone?

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An electric iron rated 250 V has a coil of resistance 125Ω. What is the cost of using it for I hour at 10k per kWh?

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If a positively charged glass-rod is used to charge an electroscope X by contact and an electroscope Y by induction, then

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