When the bottom tip of a vibrating tuning fork is held in contact with a wooden box, a louder sound is heard. This phenomenon is known as
Abeats
Bechoing
Cresonance
Dreverberation
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Question 12
jamb1991
A man hears his echo from a nearby hill 2s after he shouted. If the frequency of his voice is 260Hz and the wavelength is 1.29m, how far away is the hill?
A330.0m
B335.4m
C660.0m
D670.8m
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Question 13
jamb1991
Two tuning forks of frequency 256Hz and 260Hz are sounded close to each other. What is the frequency of the beats produced?
A2Hz
B4Hz
C8Hz
D258Hz
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Question 14
jamb1991
Which of the following correctly, describes the image of an object, 4cm from a diverging lens of focal length 12cm?
AThe image is virtual, 3cm in front of the lens
BThe image is real, 6cm behind the lens
CThe image is virtual, 6cm in front of the lens
DThe image is real, 3cm in front the lens
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Question 15
jamb1991
In a ray diagram for a thin converging lens, a ray that is not parallel to the optic axis but passes through the optic center will
Apass through undeviated
Bpass through the center of curvature after refraction
Cemerge parallel to the principal axis
Dpass through the principal focus after refraction
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Question 16
jamb1991
A trough 12.0cm deep is filled with water of refractive index \(\frac{4}{3}\). By how much would a coin at the bottom of the trough appear to be displaced when viewed vertically from above the water surface?
A3.0cm
B6.0cm
C9.0cm
D16.0cm
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Question 17
jamb1991
When a plane mirror at which a ray is incident is rotated through an angle \( \theta \), the reflected ray will be rotated through
A\(\frac{1}{2}\)\(\theta\)
B\(\theta\)
C2\(\theta\)
D3\(\theta\)
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Question 18
jamb1991
The image in a pin-hole camera is
Aerrect and formed by refraction through a lens
Bvirtual and formed by dispersion
Cerect and gets sharper as the hole becomes larger
Dinverted and formed by the light from each point travelling in a straight line
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Question 19
jamb1991
Which of the following is TRUE of light and sound waves?
Athey both transmit energy
Bthey both need a mediumfor propagation
Cthey are both transverse waves
Dtheir velocities in air are equal
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Question 20
jamb1991
A boy timed 30 oscillations of a certain pendulum thrice and obtained 1min. 10s, 1min. 12s and 1min. 7s respectively.The mean period of oscillation of the pendulum is
A0.14s
B0.43s
C2.32s
D6.97s
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Question 21
jamb1991
A room is heated by means of a charcoal fire, An occupant of the room standing away from the fire is warmed mainly by
Aconvection
Bradiation
Cconduction
Dreflection
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Question 22
jamb1991
The absolute temperature of a perfect gas is proportional to the average
Apotential energy of the molecules
Bseperation between the molecules
Ckinetic energy of the molecules
Dvelocity of the molecules
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Question 23
jamb1991
The saturated vapour pressure of a liquid increases as the
Avolume of the liquid increases
Bvolume of the liquid decreases
Ctemperature of the liquid increases
Dtemperature of the liquid decreases
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Question 24
jamb1991
How long does it take a 750W heater to raise the temperature of 1kg of water from 20oC to 50oC [specific heat capacity of water = 4200Jkg-1K-1]
A84s
B112s
C168s
D280s
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Question 25
jamb1991
What is the difference in the amount of heat given out by 4kg of steam and 4kg of water when both are cooled from 100ºC to 80ºC? [the specific latent heat of steam is 2,260,000Jkg\(^{-1}\), specific heat capacity of water is 4200Jkg\(^{-1}\)K\(^{-1}\)]
A4200J
B2,260,OOOJ
C9,040,000J
D9,380,000J
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Question 26
jamb1991
A brass rod is 2m long at a certain temperature. What is the length for a temperature rise of 100K, if the expansivity of brass is 18 x 10-6K-1?
A2.0036m
B2.0018cm
C2.1800
D2.0360m
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Question 27
jamb1991
A thermometer with an arbitrary scale S, of equal division registers -30oS at the ice point and +90oS at the steam point. Calculate the Celsius temperature corresponding to 60oS
A25.0oC
B50.0oC
C66.7oC
D75.0oC
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Question 28
jamb1991
In which of the following is surface tension important?
Athe floating of a ship in water
Bthe floating of a dry needle in water
Cthe floating of a baloon in air
Dthe diffusion of sugar solution across a membrane
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Question 29
jamb1991
A pilot records the atmospheric pressure outside its plane as 63cm of Hg while a ground observer records a reading of 75cm of Hg for the atmospheric pressure on the ground. Assuming that the density of the atmosphere is constant, calculate the height of the plane above the ground. (Relative density of Hg = 13.0 and that of air = 0.00013)
A1200m
B6300m
C7500m
D13800m
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Question 30
jamb1991
The mass of a stone is 15.0g when completely immersed in water and 10.0g when completely immersed in a liquid of relative density 2.0. The mass of the stone in air is
