2021 - JAMB Physics Past Questions and Answers - page 1
The slope of the straight line displacement-time graph indicates?
distance traveled
uniform velocity
uniform acceleration
uniform speed
Uniform velocity = \(\frac{\bigtriangleup s}{\bigtriangleup t}\)
A man will exert the greatest pressure when he?
lies flat on his back
lies on his belly
stands on both feet
stands on the toes of one foot
Pressure is inversely proportional to A, hence P \(\propto\) \(\frac{1}{A}\)
Which of the following physical quantities units are derived?
I. Area
II. Thrust
III. Pressure
IV. Mass
I, II, III and IV
I, II, and III only
I, II, and IV only
I and IV only
A ball of mass 0.5kg moving at 10ms\(^{-1}\) collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.
0.2ms\(^{-1}\)
0.5ms\(^{-1}\)
5.0ms\(^{-1}\)
5.5ms\(^{-1}\)
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\(^{1}\)
The motion of a body is simple harmonic if the?
acceleration is always directed towards a fixed point
path of motion is a straight line
acceleration is proportional to the square of the distance from a fixed point
acceleration is constant and directed towards a fixed point
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
Which of the following is not correct about the molecules of a substance in a gaseous state? They
are in a constant state of motion
have different speeds
have a temperature which is measured by the average kinetic energy
The collision between the gases is perfectly inelastic
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
A given mass of gas has a pressure of 80 Nm\(^{-2}\) at a temperature of 47 C. If the temperature is reduced to 27 C with volume remaining constant, the new pressure is?
46.0 Nm\(^{-2}\)
75.0 Nm\(^{-2}\)
80.0 Nm\(^{-2}\)
85.3 Nm\(^{-2}\)
\(\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\)
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\(^{2}\)
0.5kg of water at 10ºC is completely converted to ice at 0ºC by extracting (88000) of heat from it. If the specific heat capacity of water is 4200jkg\(^{1}\) Cº. Calculate the specific latent heat of fusion of ice.
9.0kjkg\(^{-1}\)
84.0kjkg\(^{-1}\)
134.0kjkg\(^{-1}\)
168.0kjkg\(^{-1}\)
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
Which of the following instruments may be used to measure relative humidity?
Hydrometer
Manometer
Hygrometer
Hypsometer
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.
A source of sound produces waves in air of wavelength 1.65m. If the speed of sound in air is 330ms\(^{-1}\), the period of vibration in air is?
200
0.005
0.5
0.02
v = \(\frac{\lambda}{T}\)
v = 330ms\(^{-1}\)
\(\lambda\) = 1.65m
330 = 1.65
T = \(\frac{1.65}{330}\) = 0.005s