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Pregunta 1 Informe
How much heat is required to convert 5.0g of ice at 0 ° C to water at the boiling point? (Specific latent heat of ice = 336Jg-1 specific heat capacity of water = 4.2Jg-1K-1)
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Pregunta 2 Informe
N.N.P.C. gas cylinder containing 15kg of cooking gas was left open, and the gas emptied in 3.8 minutes, at an average speed of 20 ms-1. What force was exerted on the gas in the cylinder?
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Pregunta 3 Informe
Which statements(s) is/are NOT true?
I. A saturated vapour is one that is in equilibrium with its liquid in a closed space. II. A vapour contains molecules with varying kinetic energy and their distances apart are smaller than those of the molecules of a liquid
III. Relative Humidity = \(\frac{\text{Saturated vapour pressure at dew point}} {\text{Saturated vapour pressure at air temperature}}\) x 100%
IV. The saturated vapour pressure of water increases with temperature
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Pregunta 4 Informe
Given the same amount of beat, a quantity of water will reach a higher temperature in a brass pot than in a clay pot of the same mass because
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Pregunta 5 Informe
Notes of the same frequency sounded on a piano and on a flute may differ in
I. pitch
II. quality
III. Loudness
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Pregunta 6 Informe
What is the energy stored in a 10μ F capacitor if the potential difference between the plates is 40 V?
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Pregunta 7 Informe
What is the angular velocity of an object in a horizontal circular path of radius 1.5m with a constant speed of 12ms-1?
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Pregunta 8 Informe
When an astronomical telescope is in normal adjustment, the focal length of the objective lens is 50cm and that of the eye piece is 5.0cm. What is the distance between the lenses?
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Pregunta 9 Informe
The statement that the mechanical advantage of a machine is 3 means that the
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Pregunta 11 Informe
What is X in the equation given below? 42He + 94Be → 126C + X
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Pregunta 12 Informe
The main function of the commutator in a simple d.c. motor is to
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Pregunta 13 Informe
An object is placed 15cm in front of a concave mirror of focal length 20cm. The image formed is
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Pregunta 14 Informe
The inside of a vacuum flask is usually coated with silver to reduce heat loss by
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Pregunta 16 Informe
Totally reflecting prisms are preferred to mirrors in periscopes because
I. mirror givegive multiple images
II. silvering on mirrors is easy damaged
III. mirrors reflect less light than totally reflecting prisms
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Pregunta 17 Informe
A 220 V, 60 Hz alternating current supply is connected to an inductor of 3.5H. What is the current passing through the inductor?
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Pregunta 18 Informe
An electron of charge a = 1.6 × 10-19C is situated in a uniform electric field of intensity 2.4 × 105 V m-1. What is the force on the electron?
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Pregunta 19 Informe
Which statement about the concept of temperature is NOT true?
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Pregunta 22 Informe
A metal has a work function of 3.0 eV. What is the threshold frequency of the metal when electrons are just liberated from the metal.(1 eV = 1.6 × 10-19J; h = 6.6 × 10-34Js)
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Pregunta 23 Informe
An object placed 15cm from a converging lens forms a real image whose magnification is 2.0. What is the focal length of the lens?
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Pregunta 24 Informe
A lead-acid accumulator is used in preference to a dry battery in a car because
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Pregunta 25 Informe
If N.E.P.A. charges 65 kobo per kilowatt-hour for electricity supplied to consumers, what bill would an electric iron rated at 750 watts attract when used for 24 hours?
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Pregunta 27 Informe
A transformer is connected to a 250 V a.c. supply. The primary coil has 5000 turns and the secondary voltage is found to be 10 V. What is the number of turns in the secondary coil?
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Pregunta 28 Informe
The magnetic effect of a current-carrying coil is NOT utilized in the making of a/an
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Pregunta 29 Informe
Which statement is TRUE of a block of stone of mass m, with zero momentum?
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Pregunta 30 Informe
An astronaut is walking on the moon where the magnitude of the acceleration due to gravity "g’ is one-sixth that on earth. Compared with their magnitudes on the earth, his mass and weight on the moon are
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Pregunta 31 Informe
The wavelength of a stationary wave is 24.0cm. What is the distance between a node and the next antinodes?
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Pregunta 32 Informe
A wave is represented by the equation y = 0.5 sin 0.4 Ω(X - 60t), where the distance (X) is measured in centimetres and time (t) in seconds. What is the wave length of the wave?
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Pregunta 33 Informe
The lower and upper fixed points of a mercury-in-glass thermometer are marked X and 180 mm respectively. On a particular day the mercury meniscus in the thermometer rises to 60mm. If the corresponding reading on a Celsius scale is 20 ° C, what is the value X?
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Pregunta 34 Informe
What part of a camera functions in a similar way to the retina of the eye?
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Pregunta 35 Informe
Which statement is a correct consequence of the uncertainly principle?
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Pregunta 36 Informe
A waterfall is 630m high. What is the change in temperature of a quantity of water that falls from the top to the bottom of the waterfall? (Neglect heat losses to the surroundings, take g as 10 ms-2 and specific heat capacity of weather as 4200,J kg-1K-1
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Pregunta 38 Informe
The speed of sound travelling in various media increases in the order:
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Pregunta 39 Informe
50cm3 of air at a pressure of 5Nm-2 is enclosed in a metal tube by a piston. If the piston is pushed in a distance of 10cm, what will the pressure of the air become, if the cross-sectional area of the tube is 2cm-2? (Assume that the temperature remains constant throughout)
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Pregunta 41 Informe
A cell can supply currents of 0.60 A and 0.30 A through a 2.0 ω and a 5.0 ω resistor respectively. What is the internal resistance of the cell?
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Pregunta 42 Informe
The falling of light energy on a metal such that electrons are liberated from the metal is called
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Pregunta 43 Informe
In 24 days a radioactive isotope decreases in mass from 128g to 2g. What is the half-life of the radioactive material?
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Pregunta 44 Informe
An object 3.00m high is placed at a distance of 7.50m from a pin-hole camera. If the image height is 6.00 cm, what is the distance of the film from the pin-hole?
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Pregunta 45 Informe
A body whose initial velocity is u is uniformly accelerated to a final velocity v in t seconds. If the distance travelled is s, and the acceleration is a, which equation is INCORRECT for the motion of the body?
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Pregunta 46 Informe
The invisible part of the spectrum of white light consists of
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