2021 - JAMB Physics Past Questions and Answers - page 1

The slope of a displacement-time graph represents the rate of change of displacement with respect to time. This rate of change is defined as velocity. A straight line on a displacement-time graph indicates that the velocity is constant (uniform).

Pressure is inversely proportional to A, hence P \(\propto\) \(\frac{1}{A}\)

m\(_{1}\) u\(_{1}\) + m\(_{2}\) u\(_{2}\) = (m\(_{1}\) + m\(_{2}\))v

m\(_{1}\) = 0.5kg, u\(_{1}\) = 10ms\(^{1}\), m\(_{2}\) = 0.5kg, u\(_{1}\) = 0

\(\therefore\) (0.5kg x 10) + (0.5 x 0) = (0.5 + 0.5)v

v = 5ms\(^{1}\)

In mechanics and physics, simple harmonic motion is a special type of periodic motion where the restoring force on the moving object is directly proportional to the magnitude of the object's displacement and acts towards the object's equilibrium position. Wikipedia

All collisions between gas molecules are perfectly elastic; all kinetic energy is conserved. When cars collide, energy is lost to bending bumpers and metal. Molecules do not act like this. Instead, they act like billiard balls. More

\(\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\)

P\(_{1}\) = 80Nm\(^{2}\)
T\(_{1}\) = 47 + 273 = 320k
T\(_{2}\) = 27 + 273 = 300k
P\(_{2}\)?

\(\therefore\) = P\(_{2}\) = \(\frac{P_{1}T_{2}}{T_{1}}\)

= \(\frac{80 \times 300}{320}\)

= 75.Nm\(^{2}\)

Given

Heat(H) = 88,000J,

Mass(M)= 0.5kg,

Specific heat capacity of water(C) = 4200JkgºC,

Specific latent heat of fusion(L) = ?,

Temperature change(Δθ) =  θ2 -  θ1 =  (10 - 0)° = 10°

H = MCΔθ + ML 

H = M(CΔθ + L) => \(\frac{H}{M}\) = CΔθ + L 

L = \(\frac{H}{M}\) -  CΔθ = \(\frac{88,000}{0.5}\) - 4200 \(\times\) 10

L = 176,000 - 42000 = 134,000

L = 134,000 or 134kj/kg

A hygrometer is an instrument used to measure the amount of water vapour in the air, soil, or confined spaces. Relative humidity (RH) is a measure of the amount of water vapor in a water-air mixture compared to the maximum amount possible.

v = \(\frac{\lambda}{T}\)

v = 330ms\(^{-1}\)

 \(\lambda\) = 1.65m 

330 = 1.65

T = \(\frac{1.65}{330}\) = 0.005s