The activity of a radioactive substance depends on
Atemperature and purity
Btemperature and age
Cpurity and age
Dage, purity and temperature
Enone of the above
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Question 2294
jamb1980
In the process of electrification by induction, the amount of induced charge in relation to the inducing charge is the
Asame in sign and quantity
Bsame in sign but greater
Copposite in sign but greater
Dopposite in sign but less
Eopposite in sign but equal
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Question 2295
jamb1980
According to Ohm's law, the ratio V/I is constant for
Aan electrolyte
Ba diode
Ca transistor
Dsilver
Eall of the above
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Question 2296
jamb1980
A cell has an open circuit voltage V1 and a closed circuit voltage V2 when a current is flowing through it. Therefore, the internal resistance of the cell is
A\(\frac{V_2}{I}\)
B\(\frac{V_1}{I}\)
C\(\frac{(V_1 + V_2)}{I}\)
D\(\frac{(V_1 - V_2)}{I}\)
E\(\frac{(V_2 - V_1)}{I}\)
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Question 2297
jamb1980
A man stands one-third of the way between two walls and claps his hands, He hears two distinct echoes 1s apart. If the speed of sound is 330ms-1 the distance between the wall is
A33m
B110m
C220m
D330m
E495m
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Question 2298
jamb1980
the ratio of the linear expansivity of copper to that of iron is approximately 1.5. A specimen of iron and a specimen of copper expands by the same amount per unit rise in temperature. The ratio of their length is
A3
B1.5
C1.32
D1
E0.67
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Question 2299
jamb1980
a calorimeter of thermal capacity 80j contains 20g of water at 25oC. Water at 100oC is added so that the final temperature of the set-ups is 50oC. The amount of water added is (Heat capacity of water = 4.18J/g/oC)
A20g
B25g
C45g
D50g
E100g
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Question 2300
jamb1980
Which of the following elements is the best absorber of X-rays?
Ahydrogen
Boxygen
Ccalcium
Dcopper
Elead
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Question 2301
jamb1980
Which of the following radiations cannot be deflected by a magnetic field?
A\(\alpha\)
B\(\beta\)
C\(\gamma\)
D\(\beta\) and \(\gamma\)
Enone of them
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Question 2302
jamb1980
The best material for the core of the primary and secondary coils of an induction coil is
Acopper, because it has a good conductor of electricity
Bsteel, because it becomes magnetic and retains its magnetism for a long time
Crubber, because it is a good insulator and the user is prevented from shock
Dsoft iron, because it becomes magnetic but easily loses its magnetism
Eglass, because it is transparent
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Question 2303
jamb1980
High Tension(H.T.) transmission means
Ato transmit a given amount of power, the tension in the conducting wire must be high
Bheat is not lost when current is passed through a conductor
Cheat is gained when a given power is transmitted
Da big transformer is required to transmit power
Etrasmission of power at low current and high voltage
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Question 2304
jamb1980
In sunlight, a blue flower looks blue because we see the flower by the light it
Arecieves from our eye
Bdisperses
Cabsorbs
Drefracts
Ereflects
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Question 2305
jamb1980
In a compound microscope
Athere is only one lens
Bthe objective lens have a shorter focal length than the eyepiece which is convex
Cthe objective lens has a longer focal length than the eyepiece which is convex
Dthe objective lens has a shorter focal length than the eyepiece which is concave
Ethe objective and the eyepiece are both convex and have the same focal length
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Question 2306
jamb1980
Which of the following statements about sound is NOT true?
Asound is a longitudinal wave
Bsound can be reflected and refracted like light
Csound travels through a vacuum
Dsound moves faster in a steel wire than in air
Esound can ony be produced by vibrating objects
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Question 2307
jamb1980
If the volume of a fixed mass of a gas is kept constant, the pressure of the gas
Ais inversely proprotional to its centigrade temperature
Bis inversely proportional to its absolute temperature
Cis directly proportional to its centigrade temperature
Dis directly proportional to its absolute temperature
Eremains constant also
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Question 2308
jamb1980
Heat is supplied to a block of ice 0o until half of it has melted. Which of the following statements is true?
Athe temperature rises and the ice exoands
Bthe temperature remains constant and the volume of ice decreases
Cthe ice gives out heat as it melts
Dthe mass remains constant and the temperature increases
Ethe mass decreases because some heat is lost to the atmosphere
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Question 2309
jamb1980
The relative densities of zinc, brass, copper, gold and silver are respectively 7.1, 8.5, 8.9, 19.3, 10.5. A metal ornament which weighs 0.425kg and can displace 50 x 10-6m3m of water is made of
Azinc
Bbrass
Ccopper
Dgold
Esilver
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Question 2310
jamb1980
An object of mass m and volume v, is totally immersed in a liquid of density p. The tension of a string holding it is
