All the heat generated in a 5 ohms resistor by 2A flowing for 30 seconds is used to evaporate 5g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?
A120J
B60Jg-1
C120Jg-1
D1500J
E1500Jg-1
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Question 2322
jamb1979
Which of the following electromagnetic waves has the shortest wavelength?
ARadio waves
BX-rays
CInfra-red
DBlue light
EUltraviolet
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Question 2323
jamb1979
An air bubble rises from the bottom to the top of a water dam which is 40m deep. The volume of the bubble just below the surface is 2.5cm3. Find its volume at the bottom of the dam, if atmospheric pressure is equivalent to 10m water
A0.0cm3
B2.0cm3
C1.6cm3
D0.625cm3
E0.5cm3
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Question 2324
jamb1979
Which of the following statements is true? The frequency of a vibrating string is
Aproportional to its length
Binversely proportional to the tension within it
Cproportional to the aptitude of vibration
Dinversely proportional to its cross-section
Eproportional to the square root of the tension within it
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Question 2325
jamb1979
A capacitor and a resistor are connected in series with each other and in series with an accumulator of negligible internal resistance. The potential across the terminals of the capacitor is
Atwice the e.m.f of the accumulator
Bless than the e.m.f by the potential drop across the resistor
Czero
Dthe same as the e.m.f.
Egreater than the e.m.f
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Question 2326
jamb1979
Consider a thick glass tumbler and a thin glass tumbler which are made of the same kind of glass. Some hot liquid is poured into them. Which of the following statements is correct?
Athe thick tumbler is less likely to crack because it is stronger
Bthe thick tumbler is less likely to crack because it insulates the heat beter, glass being a poor conductor of heat
CBoth tumblers are equally likely to crack because they are made of the same kind of glass
Dthe thick tumbler is more likely to crack because uneven expansion persists for a longer time within the thicker glass
Ethe thick tumbler is more likely to crack because it is heavier
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Question 2327
jamb1979
Which of the following statements about radioactivity are true? i. alpha particle is positively charged ii. Beta particle is negatively charged iii. Gamma ray is neutral iv. Beta particle has the same mass as helium atom v. Gamma ray is charged
Ai, ii, iii and iv only
Biv and v only
Ci, ii and iii only
Di, ii and v only
Eall
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Question 2328
jamb1979
In an electrolysis experiment, a cathode of mass 5g is found o weigh 5.01g after a current of 5A flows for 50 seconds. What is the electrochemical equivalent of the deposited substance?
A0.00004g/C
B0.00002g/C
C0.02500g/C
D0.05000g/C
E0.00001g/C
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Question 2329
jamb1979
The bulb of a motorcycle head-lamp is marked 40W, 6V. The resistance of the filament when it is switched on is
A\(\frac{6^2}{40^2}\)ohms
B\(\frac{40}{6^2}\)ohms
C\(\frac{40}{6}\)ohms
D6 x 40 ohms
E\(\frac{6^2}{40}\)ohms
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Question 2330
jamb1979
Which of the following is the correct definition of 'half-life'?
Athe average life-time of a radioactive material
Bthe time it takes a radioactive material to decay to half of its original quantity
Chalf the period a radioactive material decays completely
Dhalf of the decay constant
Ethe decay constant times life-time
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Question 2331
jamb1979
An electric cell has an internal resistance of 2 ohms. A current of 0.5A is found to flow when a resistor of 5 ohms resistance is connected across it. What is the electromotive force of the cell?
A5 volts
B3.5 volts
C2.5 volts
D1 volts
E10 volts
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Question 2332
jamb1979
Which of the following statements is correct? The magnetized state of an iron bar can be destroyed completely by
Aheating the bar to a high temperature
Bbreaking the bar
Cconnecting opposite poles with a small piece of iron
Dplacing the bar inside a strong magnetic field
Enone of the above
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Question 2333
jamb1979
What are the units of thermal conductivity?
Akg.m.sec2
BJoule sec-1m-1k-1
Ckg.m
DNewton sec-1m2
Em3
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Question 2334
jamb1979
Which of the following statements is correct? The reading of pressure on a mercury barometer is independent of
Athe cross-sectional area of the tube
Bthe atmospheric pressure
Cthe density of mercury
Dthe temperature of mercury
Ethe acceleration due to gravity
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Question 2335
jamb1979
A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb in his house. If he has all the points on for five hours daily and if N.E.P.A. charges 5k per unit, his bill for 30 days is
AN5.70
BN7.23
CN3.65
DN8.05
EN4.50
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Question 2336
jamb1979
Which of the following statements is incorrect? The sensitivity of a galvanometer which incorporates an optical lever arrangement may be increased by providing
Aa larger number of turns in the coil
Ba thinner suspension with a small torsional control
Ca special alloy permanent magnet which gives a high magnetic flux
Dall of the above
Ea light source with a greater intensity
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Question 2337
jamb1979
A man standing between two parallel mirrors in a barber's shop will see the following number of his own image
Aeight
Btwo
Cfour
Done
Einfinite
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Question 2338
jamb1979
If a given mass at constant pressure obeys the relation...volume is proportional to the absolute temperature...the gas is said to obey
AHooke's Law
BBoyle's Law
CDalton's Law
DCharles' Law
ENewton's Law
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Question 2339
jamb1979
An object is placed 30cm from a concave mirror of focal length 15cm. the linear magnification of the image produced is
Ao
B\(\frac{2}{3}\)
C1
D2
E3
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Question 2340
jamb1979
The heights of the mercury thread in a mercury-in-glass thermometer when in melting ice and then in steam are 3cm and 18cm respectively. At a temperature of 60oC the height would be
