2010 - JAMB Physics Past Questions and Answers - page 2

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

Inform falling on the skin causes the skin causes the sensation of warmth. since the objects are hot, the correct option is informed.

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.

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

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.

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

Radiation depends on nature of the surface area and temperature. It is independent of density.

V = fλ

f = (v)/λ = (420)/42 = 10 HZ

Period, T = (1)/F = (1)/10 = 0.1 secs

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

The lengthening effect of sound is known as reverberation.