2018 - JAMB Physics Past Questions and Answers - page 7
A solid cube of side 50cm and mass 75kg floats in a liquid with \(\frac{1}{3}\) of its height above the liquid surface. The relative density of the liquid is?
Volume of liquid displaced
= \(\frac{2}{3}\)(0.5)\(^3\)
Mass of liquid displaced = mass of floating cube = 75kg
Density of liquid = \(\frac{mass}{volume}\)
= \(\frac{75}{(\frac{7}{3(0.5)})}\) × 3
= 0.9 × 103kgm\(^{-3}\)
R.D of liquid = \(\frac{(0.9 )}{(1.0)}\) × 103
= 0.9
A man hears his echo from a nearby hill 2s after he shouted. If the frequency of his voice is 260Hz and the wavelength is 1.29m, how far away is the hill
Which of the following is an essential physical property of the wires uses for making fuses ?
A 40W instrument has a resistance 90 Ohms. On what voltage should it be operated normally
P = 40W
R = 90W
V = ?
P = \(\frac{V^2}{R}\)
V\(^2\) = PR = 40 x 90
V\(^2\) = 3000
V = √3600
V = 60N
Mercury which is spilled onto a glass surface forms ball-like shapes because____.
Water of mass 150g at 60\(^o\)c is added to 300g of water at 20\(^o\)c and the mixture is well stirred. Calculate the temperature of the mixture.(neglect heat losses to the surroundings)
Water 1 => M = 150g = 0.15kg,
θ\(_2\) = 60\(^o\)C; θ\(_1\) = θ
Q\(_1\) = MC (θ\(_2\) – θ\(_1\))
= 0.15C (60 - θ)
Water 2 => M = 300g = 0.3kg
θ1 = 20\(^o\)C, θ\(_2\) = θ
Q2 = MC (θ\(_2\) – θ\(_1\))
= 0.3C (θ – 20)
Combine Q1 & Q2, we get:
0.15C (60 - θ) = 0.3C (θ – 20)
9 – 0.15θ = 0.3θ – 6
0.3θ + 0.15θ = 9 + 6
0.45 θ = 15
θ = 33.33\(^o\)C
Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules.
Brownian motion: any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations.
The process by which protons are converted into helium atoms with a tremendous release of energy is called?
Thermionic emission: thermally induced flow of charge
Nuclear fission: nuclear reaction or a radioactive decay process
Photoelectric emission: emission of electrons or other free carriers when light shines on a material
Which of the following is not a product of nuclear fusion?
Y – Ray is a penetrating electro-magnetic radiation.
α – particle is produced in the process of alpha decay.
Neutron is a sub-atomic particle.
A room is heated by means of a charcoal fire, an occupants of the room standing away from the fire is warmed mainly by
Radiation is the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization