2006 - JAMB Physics Past Questions & Answers - page 1

1
A uniform solid cube material 10cm on each side of mass 700g is submerged in water. which of the following best described the behavior of the cube water?
A
the cube will melt after a period of time
B
the cube will float
C
the cube will sink in water
D
the cube will rest at an equilibrium position in water
CORRECT OPTION: b
For the uniform cube 10cm volume = 10 x 10 x 10 = 103 cm3
Mass = 700g
∴ density = (Mass)/Volume = (700)/100 = 0.7gcm-3
since the density is less than the density of water, the cube will float
2
At low humidity in an environment, the human skin is usually?
A
damp and rough
B
damp and smooth
C
dry and rough
D
dry and smooth
CORRECT OPTION: c
3
If the relative density of gold is 19.2, the volume of 2.4kg of gold is?
A
8.00 x 10-3 m3
B
1.25 x 10-4 m3
C
1.92 x 10-4 m3
D
4.61 x 10-3 m3
CORRECT OPTION: b
R.D = (density of the subs)/density of water
19.2 =(P)/103; ∴P = 19.2 X 103
But Vol. = (Mass)/density = (2.4)/19.2 x 103
= 1.25 x 10-4 M3
4
The thermometric property of a constant volume thermometer is?
A
change in volume
B
differential expanssion
C
change in pressure
D
change in length
CORRECT OPTION: c
The thermometric property of a constant volume thermometer is change in pressure with temperature
5
An immersion heater rated 2.0A, 240V is used to boil water from temperature 52°c to 100°c. If the mass of the water is 2.5kg. determine the time taken to boil the water.


[specific heat capacity of water = 4.2 x 103 jkg-1 k-1]
A
1.05 x 103s
B
1.05 x 105s
C
1.05 x 102s
D
1.05 x 104s
CORRECT OPTION: a
Power of heater = lvt = 2 x 240 x t
heat required to boil the water = Mct = 2.5 x 4.2 x 103 x (100.52) = 2.5 x 4. 2 x 103 x 48
2 x 240 x t = 2.5 x 4.2 x 103 x 48
∴ t = (2.5 x 4.2 x 103 x 48)/2 x 240
= 1050s or 1.05 x 103s
6
The thermos flask is designed to?
A
prevent heat loss or gain by conduction, convection amd radiation
B
store hot tea or water
C
prevent heat gain by conduction, convection and radiation
D
prevent head lost conduction, convention and radiation
CORRECT OPTION: a
7
what is likely to happen if the glass of a thermometer expands more upon heating than the liquid inside?
A
the glass will break
B
the glass will shrink
C
the liquid will rise up in the stem
D
the liquid will go down in the stem
CORRECT OPTION: d
8
A drop of petrol makes a finger colder than a drop of water would because?
A
petrol takes its latent heat of veporization from the finger
B
petrol takes its latent heat of fusion from the finger
C
water is more viscious than petrol
D
water has higher surface tension dan petrol
CORRECT OPTION: a
9
A cell of internal resistance r is connected to an external resistor R. The conductor for maximum power transfer is?
A
R < r
B
R = r
C
R = 2r
D
R > r
CORRECT OPTION: d
p is the time rate of expending energy. for electrical energy, P = IV; 12R or (V)/R. For a cell of constant e.m.f (voltage) maintaining constant current(1) through the circuit, P α R; OR (1)/R.
Again for maxi. power,p α R
And with respect to the opinion, maxi power would be transferred when R>r:not necessarily R = 2r
10
The production and type of charge of a body can only be accounted for by the?
A
deficiency or surplus of electrons
B
equibrium in protons and neutrons
C
deficiency or surplus of protrons
D
deficiency or surplus of neutrons
CORRECT OPTION: a
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