2000 - JAMB Physics Past Questions and Answers - page 2

11
A quantity of water at 0°C is heated to about 30°C. At each degree rise in temperature, its density will
A
rise steadily
B
fall steadily
C
fall then rise
D
rise then fall
correct option: d
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12
I. Coherence
II. Same frequency
III. Same wavelength
IV. Same Intensity

Which of the conditions above are necessary to produce interference fringes?
A
I and III
B
I, II and IV
C
I, II and III
D
II and III
correct option: c
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13
A boy observes a piece of stone at the bottom of a river 6.0m deep. If he looks from the surface of the river, what is the apparent distance of the stone from him? [Refractive Index of Water = 4/3]
A
8.0m
B
5.5m
C
5.0m
D
4.5m
correct option: d
Refractive Index = Real Depth/App. Depth
4/3 = 6/app. depth
App Depth = (3 x 6)/4 = 4.5m
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14
A thin wire with heavy weights attached to both ends is hung over a block of ice resting on two supports. If the wire cuts through the ice block while the block remains solid behind the wire, the process is called
A
condensation
B
sublimation
C
regelation
D
fusion
correct option: c
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15
Dry
Day 1 - 30°C | Day 2 - 29°C | Day 3 - 25°C

Wet
Day 1 - 22°C | Day 2 - 22°C | Day 3 - 21°C

The reading above are for three consecutive days from a wet and dry bulb hygrometer. It can be concluded that the relative humidity for the three days
A
decreased steadily
B
remained unchanged
C
increased steadily
D
was least on Day 1
correct option: c
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16
One end of a long wire is fixed while a vibrator is attached to the other end. When the vibrator is energized, the types of waves generated in the wire are
A
stationary and longitudinal
B
stationary and transverse
C
progressive and transverse
D
progressive and longitudinal
correct option: c
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17
A metal of mass 0.5kg is heated to 100°C and then transferred to a well-lagged calorimeter of heat capacity 80JK-1 containing water of heat capacity 420JK-1 at 15°C. If the final steady temperature of the mixture is 25°C, find the specific heat capacity of the metal.
A
877Jkg-1K-1
B
286Jkg-1K-1
C
133Jkg-1K-1
D
92Jkg-1K-1
correct option: c
Let the specific heat cap. of the metal = C
∴ Heat lost by the metal = heat gained by the Calorimeter + Water
∴ 0.5 x C x [100 - 25]
80 x [25 - 15] + 420 [25 - 15]
0.5 x C x 75 = 80 x 10 + 420 x 10
37.5C = 800 + 4200
C = 5000/37.5 = 133.3Jkg-1K-1
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18
The main reason for making the cover of a vacuum flask airtight is to prevent heat loss by
A
convection
B
conduction
C
radiation
D
evaporation
correct option: a
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19
A radio is operated by eight cells each of e.m.f. 2.0V connected in series. If two of the cells are wrongly connected, the net e.m.f. of the radio is
A
8V
B
10V
C
12V
D
16V
correct option: c
Net e.m.f = (8 x 2) - (2 x 2)

= 12V
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20
If a charged ion goes through combined electric and magnetic fields, the resultant emergent velocity of the ion is
A
E/B
B
EB
C
B/E
D
E - B
correct option: a
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