Q7052.Two liquids X and Y having the same mass are supplied with the same quantity of heat. If the temperature rise in X is twice that of Y, the ratio of specific heat capacity of X to that of Y is
A$2:1$
B$1:2$
C$4:1$
D$1:4$
Correct Answer: B
$Q = mc\Delta T$. $\dfrac{c_X}{c_Y} = \dfrac{\Delta T_Y}{\Delta T_X} = \dfrac{1}{2}$. Ratio is $1:2$.
JAMB (UTME)
Physics
2013
Q7053.Foods cook quicker in salt water than in pure water because of the effect of
Adissolved substances on the boiling point
Batmospheric pressure on the boiling point
Cfood nutrients on the thermal energy
Dsalts on the thermal conductivity of water.
Correct Answer: A
Dissolved salts raise the boiling point of water, allowing food to cook at a higher temperature.
JAMB (UTME)
Physics
2013
Q7054.Steam from boiling water causes more damage on the skin than does boiling water because
Awater has a high specific heat
Bsteam has latent heat of fusion
Cthe steam is at higher temperature than the water
Dsteam brings heat more easily by convection.
Correct Answer: B
Steam releases its latent heat of vaporization when it condenses on the skin, causing more severe burns. (Note: The correct term is latent heat of vaporization, not fusion. The answer key B is the intended answer).
JAMB (UTME)
Physics
2013
Q7055.What will happen to the boiling point of pure water when it is heated in a place $30 \mathrm{m}$ below sea level?
AIt will be lower
BIt will be higher
CIt will remain the same
DIt will be unpredictable.
Correct Answer: B
At a place below sea level, atmospheric pressure is higher, so the boiling point of water increases.
JAMB (UTME)
Physics
2013
Q7056.The rise or fall of liquid in a narrow tube is because of the
Aviscosity of the liquid
Bsurface tension of the liquid
Cfriction between the walls of the tube and the liquid
Dosmotic pressure of the liquid.
Correct Answer: B
Capillarity is due to surface tension and adhesion/cohesion forces.
JAMB (UTME)
Physics
2013
Q7057.The mechanism of heat transfer from one point to another through the vibration of the molecules of the medium is
Aconvection
Bconduction
Cradiation
Ddiffusion.
Correct Answer: B
Conduction is the transfer of heat through molecular vibration without bulk movement of the medium.
JAMB (UTME)
Physics
2013
Q7058.A wave travels through stretched strings is known as
Aelectromagnetic wave
Bmicro wave
Cmechanical wave
Dseismic wave.
Correct Answer: C
Waves on a stretched string are mechanical waves.
JAMB (UTME)
Physics
2013
Q7059.A transverse wave and a longitudinal wave travelling in the same direction in a medium differ essentially in their
Afrequency
Bamplitude
Cdirection of vibration of the particles of the medium
Dperiod of vibration of the particles of the medium.
Correct Answer: C
The difference is that in transverse waves, particles vibrate perpendicular to the direction of travel, while in longitudinal waves, they vibrate parallel.
JAMB (UTME)
Physics
2013
Q7060.What is the velocity of sound at $100^{\circ}\mathrm{C}$, if the velocity of sound at $0^{\circ}\mathrm{C}$ is $340 \mathrm{ms}^{-1}$?
Q7061.If a sonometer has a fundamental frequency of $450 \mathrm{Hz}$, what is the frequency of the fifth overtone?
A$2250 \mathrm{Hz}$
B$2700 \mathrm{Hz}$
C$450 \mathrm{Hz}$
D$900 \mathrm{Hz}$
Correct Answer: B
Fifth overtone is the 6th harmonic. $f_6 = 6 \times 450 = 2700 \mathrm{Hz}$.
JAMB (UTME)
Physics
2013
Q7062.A man $1.5 \mathrm{m}$ tall is standing $3 \mathrm{m}$ in front of a pinhole camera whose distance between the hole and the screen is $0.1 \mathrm{m}$. What is the height of the image of the man on the screen?
Q7063.A ray of light passing through the centre of curvature of a concave mirror is reflected by the mirror at
A$0^{\circ}$
B$45^{\circ}$
C$90^{\circ}$
D$180^{\circ}$
Correct Answer: A
A ray passing through the centre of curvature is incident normally on the mirror and is reflected back along the same path, so the angle of reflection is $0^{\circ}$.
JAMB (UTME)
Physics
2013
Q7064.From the diagram below, calculate the incident angle $i$. [Glass $n = 1.52$, Water $n = 1.33$]
A$41^{\circ}$
B$49^{\circ}$
C$55^{\circ}$
D$61^{\circ}$
Correct Answer: A
Using Snell's law at the glass-water interface: $n_g \sin i = n_w \sin r$. The diagram indicates the refracted ray is along the interface, so $r = 90^{\circ}$. $1.52 \sin i = 1.33 \sin 90^{\circ}$. $\sin i = \dfrac{1.33}{1.52} = 0.875$. $i = 61^{\circ}$. The answer key A is incorrect; the correct answer is D.
JAMB (UTME)
Physics
2013
Q7065.Total internal reflection will not occur when light travels from
Awater to air
Bwater into glass
Cglass to air
Dglass into water.
Correct Answer: B
Total internal reflection requires light to travel from a denser to a less dense medium. Water is less dense than glass, so it cannot occur.
JAMB (UTME)
Physics
2013
Q7066.What does the diagram above represent?
Atelescope in normal use
Bmicroscope in normal use
Cprojector
Dperiscope
Correct Answer: A
The diagram shows two convex lenses arranged as an astronomical telescope in normal adjustment.
JAMB (UTME)
Physics
2013
Q7067.If the linear magnification of the objective and eyepiece convex lenses of a compound microscope are $4$ and $7$ respectively, calculate the angular magnification of the microscope.
Q7068.The angle of deviation of light of various colours passing through a triangular prism increases in the order
Ared $\rightarrow$ green $\rightarrow$ blue
Bgreen $\rightarrow$ violet $\rightarrow$ blue
Cblue $\rightarrow$ red $\rightarrow$ green
Dblue $\rightarrow$ green $\rightarrow$ red
Correct Answer: A
Deviation increases from red (least deviated) to violet (most deviated). So red, green, blue is correct.
JAMB (UTME)
Physics
2013
Q7069.Calculate the force acting on an electron of charge $1.5 \times 10^{-19} \mathrm{C}$ placed in an electric field of intensity $10^5 \mathrm{Vm}^{-1}$.
Q7070.Capacitors are used in the induction coil to
Acontrol circuits
Bdissipate energy
Cprevent electric sparks
Dprevent distortion of electric fields.
Correct Answer: C
Capacitors in an induction coil suppress sparking at the contact breaker.
JAMB (UTME)
Physics
2013
Q7071.A cell of emf $1.5 \mathrm{V}$ is connected in series with a $1 \Omega$ resistor and a current of $0.3 \mathrm{A}$ flows through the resistor. Find the internal resistance of the cell.
Q7073.A house has ten $40 \mathrm{W}$ and five $100 \mathrm{W}$ bulbs. How much will it cost the owner of the house to keep them lit for $10$ hours if the cost of a unit is ₦5?
Q7075.When a charge moves through an electric circuit in the direction of an electric force, it
Agains both potential and kinetic energy
Bgains potential energy and kinetic energy
Closes potential energy and gains kinetic energy
Dloses both potential and kinetic energy.
Correct Answer: C
A charge moving in the direction of the electric force loses potential energy and gains kinetic energy.
JAMB (UTME)
Physics
2013
Q7076.To convert a galvanometer to voltmeter, a
Ahigh resistance is connected to it in series
Bhigh resistance is connected to it in parallel
Clow resistance is connected to it in series
Dlow resistance is connected to it in parallel.
Correct Answer: A
A high resistance is connected in series with a galvanometer to convert it to a voltmeter.
JAMB (UTME)
Physics
2013
Q7077.Induced emfs are best explained using
AOhm's law
BFaraday's law
CCoulomb's law
DLenz's law.
Correct Answer: B
Faraday's law of electromagnetic induction explains induced emfs.
JAMB (UTME)
Physics
2013
Q7078.If a current of $2.5 \mathrm{A}$ flows through an electrolyte for $3$ hours and $1.8 \mathrm{g}$ of a substance is deposited, what is the mass of the substance that will be deposited if a current of $4 \mathrm{A}$ flows through it for $4.8$ hours?
Q7080.In photo-emission, the number of photoelectrons ejected per second depends on the
Afrequency of the beam
Bwork function of the metal
Cthreshold frequency of the metal
Dintensity of the beam.
Correct Answer: D
The number of photoelectrons emitted per second is proportional to the intensity of the incident light.
JAMB (UTME)
Physics
2013
Q7081.The particle nature of light is demonstrated by the
Aphotoelectric effect
Bspeed of light
Ccolours of light
Ddiffraction of light.
Correct Answer: A
The photoelectric effect demonstrates the particle nature of light.
JAMB (UTME)
Physics
2013
Q7082.The energy of a photon having a wavelength of $10^{-10} \mathrm{m}$ is [h $= 6.63 \times 10^{-34} \mathrm{Js}$, c $= 3.0 \times 10^8 \mathrm{ms}^{-1}$]
Q7092.An object of weight $80 \mathrm{kg}$ on earth is taken to a planet where acceleration due to gravity is one-third of its value on earth. The weight of the object on the planet is
A$48 \mathrm{N}$
B$12 \mathrm{N}$
C$27 \mathrm{N}$
D$36 \mathrm{N}$
Correct Answer: A
Weight on earth $= 80 \times 10 = 800 \mathrm{N}$. Weight on planet $= \dfrac{800}{3} = 266.7 \mathrm{N}$. The answer key A is incorrect. The correct answer is not listed. (Note: The question likely meant mass of $80 \mathrm{kg}$, but the weight calculation is $266.7 \mathrm{N}$).
JAMB (UTME)
Physics
2014
Q7093.One of the conditions necessary for an object to be in equilibrium when acted upon by a number of parallel forces is that the vector sum of the forces is
AAverage
BZero
CNegative
DPositive
Correct Answer: B
For equilibrium, the vector sum of all forces (resultant) must be zero.
JAMB (UTME)
Physics
2014
Q7094.What happens when three coplanar non-parallel forces are in equilibrium?
ATheir lines of action are parallel.
BThey are represented in magnitude only
CThey are represented in direction only
DTheir lines of action meet at a point
Correct Answer: D
Three non-parallel forces in equilibrium must be concurrent (their lines of action meet at a point).
JAMB (UTME)
Physics
2014
Q7095.An object of mass $20 \mathrm{kg}$ is released from a height of $10 \mathrm{m}$ above the ground level. The kinetic energy of the object just before it hits the ground is
Q7096.The energy in the nucleus of atoms produce heat which can be used to generate
AKinetic energy
BMechanical energy
CElectrical energy
DPotential energy
Correct Answer: C
Nuclear energy is used to generate electrical energy in power stations.
JAMB (UTME)
Physics
2014
Q7097.A machine whose efficiency is $75\%$ is used to lift a load of $1000 \mathrm{N}$. Calculate the effort put in to the machine if it has a Velocity ratio of $4$.
Q7098.A wheel and an axle is used to raise a load whose weight is $800 \mathrm{N}$ when an effort of $250 \mathrm{N}$ is applied. If the radii of the wheel and axle are $800 \mathrm{mm}$ and $200 \mathrm{mm}$ respectively, the efficiency of the machine is
Q7100.From the diagram above, the point that represent the elastic limit is
AQ
BR
CS
DT
Correct Answer: B
The elastic limit is the point beyond which the material will not return to its original length when the load is removed. This is point R on the stress-strain curve.