2010 - JAMB Physics Past Questions and Answers - page 2
11
The density of a certain oil on frying becomes
0.4 kgm-3 with the volume of 20m3. what will be its initial volume when its initial density is 0.8 kgm-3 assuming no loss of oil due to spillage?
0.4 kgm-3 with the volume of 20m3. what will be its initial volume when its initial density is 0.8 kgm-3 assuming no loss of oil due to spillage?
A
12 kgm-3
B
10 kgm-3
C
8 kgm-3
D
5 kgm-3
correct option: b
Density, p = (mass)/volume (m)/(v)
0.4 = (m)/20
∴ m = 20 x 0.4 = 8 kg
V = (m)/p = (8)/0.8 = 10 m3
N:B the units for the options are wrong
Users' Answers & Comments0.4 = (m)/20
∴ m = 20 x 0.4 = 8 kg
V = (m)/p = (8)/0.8 = 10 m3
N:B the units for the options are wrong
12
Heat is radiated by hot objects in the form
A
x-rays
B
light energy
C
infrared rays
D
solar energy
correct option: c
Inform falling on the skin causes the skin causes the sensation of warmth. since the objects are hot, the correct option is informed.
Users' Answers & Comments13
If a container is filled with ice to the brim, what happens to the level of water when the ice completely melts?
A
the level of water goes up
B
the water in the glass outflows
C
the level of water remains unchanged
D
the level of water drops
correct option: d
Due to anomalous expansion of water at temperature range (0 - 4)°c, when a given mass of water turns into ice, its volume will increase, while the mass remains constant. Thus, when a given volum of ice melts, the volume of water formed will be less than the volume of ice. Hence, the level of water in the container will drop.
Users' Answers & Comments14
The small droplet of water that forms on the grass in the early hours of the morning is
A
hail
B
dew
C
fog
D
mist
correct option: b
Dew point is the temperature at which the water vapour present in air is just sufficient to saturate it. Dew is formed when air is cooled below its dew point
Users' Answers & Comments15
A vapour is said to be saturated when
A
a dynamic equilibrium exists between liquid molecules and the vapour molecules
B
a dynamic aquilibrium exists such that more molecules return to the liquid than are living it
C
the temperature of the vapour varies
D
the vapour pressure is atmospheric
correct option: a
A saturated vapour is one which is in dynamic equilibrium with its own liquid; that is as many go from the liquid to the vapour state every second return back to liquid.
Users' Answers & Comments16
The pressure of one mole of an ideal gas of volume 10-2 m3 at a temperature of 27°c is
[molar gas constant = 8.3 J mol-1 k-1]
[molar gas constant = 8.3 J mol-1 k-1]
A
2.49 x 104 Nm-2
B
2.24 x 104 Nm-2
C
2.49 x 105 Nm-1
D
2.24 x 105 Nm-1
correct option: c
T = 27 + 273 = 300 K, volume, V = 10-2 m3 molar gass constant, R = 8.3 Jmol- 1k - 1 number of mole, n = 1
PV = NRT
i.e P = (NRT)/V = (1 x 8.3 x 300)/10-2
= 2.49 x 105 Nm-1
Users' Answers & CommentsPV = NRT
i.e P = (NRT)/V = (1 x 8.3 x 300)/10-2
= 2.49 x 105 Nm-1
17
Which of the following has no effect on radiation?
A
nature of surface
B
density
C
surface area
D
temperature
correct option: b
Radiation depends on nature of the surface area and temperature. It is independent of density.
Users' Answers & Comments18
The wavelength of a wave traveling with a velocity of 420 ms-1 is 42 m. what is its period?
A
1.2 s
B
1.0 s
C
0.5 s
D
0.1 s
correct option: d
V = fλ
f = (v)/λ = (420)/42 = 10 HZ
Period, T = (1)/F = (1)/10 = 0.1 secs
Users' Answers & Commentsf = (v)/λ = (420)/42 = 10 HZ
Period, T = (1)/F = (1)/10 = 0.1 secs
19
The sound of an electricity bell dies down slowly when air is slowly pumped out from a bottle because
A
the wavelength of sound becomes greater in the bottle
B
sound cannot pass through the bottle
C
sound needs a material medium
D
sound can pass through a vacuum
correct option: c
Sound wave requires a material medium for its propagation. so when air is being pumped out the density of the medium is being reduced and the sound dies down. when all the air has been pumped out of the glass, no sound will be heard, as sound sound cannot travel through vacuum
Users' Answers & Comments20
During a thunderstorm, the sound is heard over a long time. this phenomenon is referred to as
A
diffraction of sound
B
refraction of sound
C
superposition
D
reveraberation
correct option: d
The lengthening effect of sound is known as reverberation.
Users' Answers & Comments