DELTA STATE UNIVERSITY, ABRAKA

JOINT UNIVERSITIES PRELIMINARY EXAMINATIONS BOARD

JULY 2023 MOCK EXAMINATIONS

PHYSICS Time Allowed: 3 hours

SECTION A: MULTIPLE CHOICE QUESTIONS

Answer all questions in this section

SECTION B: ESSAY QUESTIONS
Answer FOUR questions; ONE question from each course.
The following constants are given

Acceleration due to gravity, g 9.8m/s2

Atomic mass unit, u 931.5MeV = 1.661 x 10-27kg
Avogadro’s number, NA 6.02 x 1023mol-1
Boltzmann constant, k 1.38 x 10-23J/K
Density of water, 𝜌𝑤 1000 kg/m3
e/m 1.76 x 1011 C kg-1
Electric charge, e 1.6 x 10-19C
Electron rest mass, me 9.11 x 10-31kg
Electron volt, eV 1.602 x 10-19J
Gravitational constant, G 6.67 x 10-11Nm2 /kg2
Mass of Helium nucleus 4.0015u
Mass of neutron 1.0087u
Molar gas constant, R 8.31 J/K/mol
Permeability of free space (μ0) 4ᴫ x 10−7Hm−1
Permittivity of free space ( 0 ) 8.85 x 10-12F/m
Planck’s constant, h 6.6 x 10-34Js
Proton rest mass, mp 1.67 x 10-27kg
Radius of the earth, R 6.4 x 106m
Refractive index for glass 1.5
Refractive index for water 1.33
Speed of light in vacuum, c 3.0 x 108 m/s
Stefan constant, 𝜍 5.67 x 10-8 W/(m2 k 4 )
Wien constant, 𝛼 2.9 x 10-3 Mk
(4𝜋𝜀𝑜) -1 9.0 x 109 mF-1
1 atm 1.105 x 105 Pa

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SECTION A: MULTIPLE CHOICE QUESTIONS. Answer ALL questions.

1. What is the resultant of two forces inclined at an angle 40 0 to each other with each having a
magnitude of 3N and 4N respectively?
(A) 6.6 N (B) 5 N (C) 7 N (D) 1 N
2. Given that two vectors ⃗ and ⃗⃗ . Their dot product is given as
(A) 11 (B) -11 (C) 15 (D) 20
3. Calculate the instantaneous speed of a car moving according to the equation.

x  t 3  5t 2  3t  10 at a time t = 2s.
(A) 24 m/s (B) (C) 30 m/s (D) 35 m/s
4. A marble dropped from a bridge strikes the water in 5.02. Calculate the speed at which it strikes
the ground
(A) 50.2 m/s (B) 0.502 m/s (C) 5.0 m/s (D) 25 m/s
5. A body projected upward from the level ground at an angle of 500 with the horizontal has an
initial speed of 40mls (a) how long will it take to hit the ground. (Take g = 9.8 m/s 2).
(A) 6.25s (B) 100 s (C) 40 s (D) 20 s
6. When taking a penalty kick, a footballer applies a force of 40N for a period of 0.065. If the mass
of ball is 0.075kg, calculate the impulse of the ball.
(A) 25 ns (B) 2.4 ns (C) 24 ns (D) 32 ns
7. A block and tackle system is used to lift a load of 20 N through a vertical height of 10 m. if the
efficiency of the system is 40 %, how much work is done against friction?
(A) 300 J (B) 120 J (C) 400 J (D) 500 J
8. Where r is the radius of the small piston and R is the radius of the large piston. For a hydraulic
press, the velocity ratio is given as
R2 r 2r 1
(A) V .R  2
(B) V .R  (C) V .R  (D) V .R 
r R R sin R
9. The earth has a radius of 6380 km and turns around once on it axis in 24 hours. What is the radial
acceleration of an object at the earth’s equator?
(A) 0.034 m/s2 (B) 34 m/s2 (C) 3.4 m/s2 (D) 0.34 m/s2
10. A cylinder 0.9 m deep is full of liquid mercury of density 13.6×103 kgm-3. At what depth below
the surface will its pressure equal to 1650 Nm-2 ?
(A) 0.8 m (B) 80 m (C) 16 .5 m (D) 0.4 m

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11. If momentum (P), area (A) and time (T) are taken to be fundamental quantities, then energy has
the dimensional formula
(A) P A-1T (B) P2AT (C) PA-1/2T (D) PA1/2T-1
12. If the force applied in the direction of motion of a certain object on a horizontal frictionless
surface is halved, the acceleration of the object is
(A) Doubled (B) Constant (C) 0 (D) Halved
13. Consider a pair of particle separated by a distance D. If the masses are m1 and m2 such that m2 is
3/2 of m1. What is the position of their centre of mass if they are connected by a light rod
(A) D/2 (B) 3/5D (C) 4/3D (D) D
14. For a simple pulley whose number of movable pulley is n, the velocity ratio is given as
(A) n (B) 1/sinθ (C) a/b (D) 2n
15. If the mass number of iron is 56, find the radius given that the constant is . (A)
4.6 fm (B) 4 pm (C) 5.2 fm (D) 5.2 pm
16. According to the Stefan-Boltzmann law of thermal radiation, the rate of radiant energy per unit
area is proportional to the
A. temperature of that radiator B. Square of the temperature of that radiator C. cube of the
temperature of that radiator D. fourth power of the temperature of that radiator
17. The instrument used in marking the upper fixed point of thermometer is known as
A. hypsometer B. manometer C. spectrometer D. thermometer
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18. A beaker is filled with water at 4 C. At one time the temperature is increased by few degrees
above 4oC and at another time it is decreased by a few degrees below 4 oC. Which of the
following is correct?
A. The level of water remains constant in each case. B. In first case water overflows while in
second case its level reduces. C. In second case water overflows while in first case its level
reduces. D. Water overflows in both cases.
19. Find the pressure of two moles of an ideal gas at a temperature of 27 0C and volume 10-2 m3 .
A. 4.99 x 105 N/m2 B. 9.80 x 103 N/m2 C. 4.98 x 103 N/m2 D. 9.80 x 105 N/m2

20. Determine the rate of radiant emission per m2 for a blackbody at 25oC
A. 396 W B.447 W C.445 W D.430 W
21. The temperature of a liquid that is boiling does not increase even though heat is being
continuously supplied because
A. Heat supplied is used to break the molecular bonds in the liquid B. There are impurities in the

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 liquid C. The latent heat of fusion of the light is greater than the latent heat of vapourization D.
The atmospheric pressure is high
22. Which of the following properties are NOT those of a suitable thermometric liquid?
I. It should be a good conductor of heat
II. It should be opaque
III. Its expansion should be regular
IV. It should wet glass
V. It should have a high melting point and low boiling point
A. I and II B. I and III C. II and III D. IV and V
23. The gas model which considers the gas molecules to be small particles which are far apart, and
move randomly at high speed and colliding elastically is called……
A. The real gas theory B. The molecular gas theory C. The kinetic gas theory
D. The atomic gas theory
24. Standing waves are produced by the interference of two traveling sinusoidal waves, each of
frequency 100 Hz. The distance from the second node to the fifth node is 60 cm. The wavelength
of each of the two original waves is
A. 40 cm B. 50 cm C. 30 cm D. 20 cm
25. Microwave is an example of electromagnetic wave while radio wave is an example of
A. sound wave. B. non-periodic wave. C. longitudinal wave. D. electromagnetic wave
26. A body emit 60 cycles per second of a progressive wave travelling at 20 m/s. What is the
wavelength of the wave?
A. 5.12 m B. 0.33 m C. 2.5 m D. 0.50 m
27. In a double slit experiment, the distance between the fringes on the screen was too small to
measure, what would increase distance between the fringes on the screen?
A. increase the distance between the slits and the screen B. increase the distance between the
light source and the slits C. increase the distance between the slits D. increase the
frequency of the light source

28. What is the critical angle of light passing from a material of index of refraction 1.54 to a material
of index of refraction n = 1.33? A. 0 o B. 59.7o C. 55.7o D. 90.0o
29. A boy observes a piece of stone at the bottom of a river 6.0 deep. If he looks vertically from
the surface of the river, how far does the stone appear to be from him?
A. 8.0 B. 4.5 C. 6.0 D. 5.5

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30. A man stands 50 cm from a concave mirror with radius of curvature 10 cm. find the position and
magnification of the image
A. 5.56 cm, 0.11 B. 5.56cm, 0.12 C.7.55cm, 0.11 D.7.89cm, 0.14
31. An X-ray tube takes a current of 7.0 and operates at a potential difference of 80 𝑉. What
power is dissipated? A. 460 𝑊 B. 560 𝑊 C. 660 𝑊 D. 760 W
32. Which of the following are true about electric lines of force? I. They terminate from positive
charges II. They terminate on negative charges III. They intersect each other IV. They repel each
other
A. I, II, III and IV B. I and II only C. I, II and IV only D. I and III only
33. The force between two charges is 120 N. If the distance between the charges is doubled, the
magnitude of the force will be?
A. 60 N B. 30 N C. 40 N D. 15 N
34. A work of 30𝐽 is done in transferring 5 𝐶 of charge from a point to a point in an electric
field. The potential difference between and is
A. 1.5𝐾𝑣 B. 0.2𝐾𝑣 C. 3𝐾𝑣 D. 6𝐾𝑣
35. The direction of force on a current-carrying conductor placed in a magnetic field can be found by
A. Cork screw rule B. Fleming’s left hand rule C. Fleming’s right hand rule D. Using a compass
36. An electron moves in a circular path of radius 0.03 perpendicular to a uniform magnetic field.
The electron has a velocity of 106 /𝑠. Find the magnitude of the uniform field. A. 1.90 ×
10−3𝑊𝑏 −2
B. 5.69 × 10−3𝑊𝑏 −2
C. 5.69 × 10−3𝑊𝑏 −2
D. 6.89 × 10−3𝑊𝑏 −2

37. A wire 50 long carries a 25 current. If it is placed in a magnetic field ⃗⃗ = 0.2𝑇, what is
the force on the wire? A. 1.20𝑁 B. 2.50𝑁 C. 0.25𝑁 D. 0.20𝑁
38. A coil of wire with N turns and area A is placed into a magnetic field of magnitude B. The angle
of the normal to the plane of the coil is at an angle  with respect to the magnetic field.
According to Faraday’s law, which of the following changes will produce an emf in the coil?
I. B is decreased II. A is increased III.  is decreased
A. I only. B. I and III only. C. II and III only. D. I, II and III.
39. The magnetic flux in a coil having 500 turns changes at the time rate of 0.04 wbs−1. What is the
induced e.m.f in the coil?
A. 20 V B. 50 V C. 10 V D. 5 V
40. The essential parts of an a.c generator consist of the following EXCEPT
A. Field magnet B. Slip rings C. Split rings D. Brushes

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41. _______________ is defined as the summation of the protons and neutrons in the nucleus.
(A) Atomic number (B) neutron number (C) nucleon number (D) proton number.
42. The conclusion of the _________ of atom is that the atom is a sphere of positively charged
particles (protons) in which negatively charged particles (electrons) are embedded and spread
equally throughout like raisins in a muffins
(A) Rutherford’s model (B) J.J Thompson’s model (C) Bohr’s model (D) Milikan’s
model
43. When elements have the same number of protons but different mass number, it is called
________.
(A) entropy (B) isotopes (C) ionization (D) isotopy
44. _______________ is defined as the amount of kinetic energy gained or lost by a single electron
accelerating from rest through an electric potential difference of one volt in vacuum.
(A) an electron volts (B) the joules (C) one volt (D) the frequency of radiation
45. The minimum amount of energy required by an individual electron to escape from a particular
surface is called ____________
(A) threshold frequency (B) stopping potential (C) energy radiated (D) work
function
46. The plot of electron kinetic energy T against the frequency of the incident light on a metal
surface gives an intercept on the frequency axis. What is the significance of this intercept
(A) work function (B) stopping potential (C) threshold frequency (D) energy
radiated
47. A metal has a work function 3.0eV illuminated by light of wavelength 0.6 nm. Calculate the
threshold frequency
(A) (B) (C) (D) none of the above.
48. Given that 𝜍 is called the Stefan-Boltzmann constant. What is the unit of this constant
(A) 𝑊𝐾 (B) 𝑊𝐾 (C) 𝑊𝐾 (D)
49. A 𝐾 x-ray emitted from a sample has an energy of 7.46 keV of which element is the sample
made?
(A) copper (B) Nickel (C) aluminum (D) cobalt
50. What is the de Broglie’s wavelength of an electron with a kinetic energy of 120 eV?
(A) 112 nm (B) 112 fm (C) 112 pm (D) 112 µm

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SECTION B: ESSAY QUESTIONS

Answer FOUR Questions in ALL; ONE from each Course

PHY 001: MECHANICS AND PROPERTIES OF MATTER

1. (a) Given the coordinate of a particle in meters is given by X (t) = 16t – 3t2, where the time t
is in seconds. The particle is momentarily at rest at t =?
(i) Find the Instantaneous velocity [3 Marks]
(ii) The position of the particle momentarily at rest [3 Marks]
(iii) The electromagnetic pointing vector S is defined as S=E×H, where E and H are the
electric and magnetic fields respectively. E = 10.10i + 0.20j + 0.60k and H = 0.40i +
9,80j + 0.10k. What is the value of S. [4 Marks]
2. (i) Given that the time by the relation T  K x r y  z where ρ depicts the density, γ is the
surface and r is the radius. Using dimensional analysis deduce the value of x, y, and z.
[3 Marks]

(ii) State Keplars law of planetary motion [3 Marks]

(iii) State Hooke’s law of elasticity and hence solve: compute the volume change of a solid
copper cube, 40 mm on each edge, when subjected to a pressure of 20 MPa. The bulk modulus
for copper is 125 GPa. [4 Marks]

PHY 002: HEAT, WAVES AND OPTICS

3. (a) Define the following terms and state their units:

(i) Specific heat capacity [2 Marks]

(ii) Specific latent heat [2 Marks]

(b) A plane-progressive wave is represented by the equation

y  3.0sin (400t  0.2x) m. If all the variables are in S.I. units, Calculate the:
(i) amplitude; (ii) frequency; (iii) wavelength; and (iv) speed of the wave.
[4 Marks]

(c) The length of a test-tube is 15cm. Calculate the two lowest frequency for the sound when
the string is plucked. Take the speed of sound in air as 330 m/s. [2 Marks]

4. (a) Explain the following terms

(i) Critical angle

(ii) Total internal reflection [2 Marks]

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 (b) The angle of incidence of a light ray from air to another medium is 30°, while it was
refracted in the second medium at an angle of 22°. What is the refractive index in the
second medium? [2 Marks]

(ii) A ray of light travelling in crown glass of refractive index 1.52 is incident on glass-air
interface. Calculate the critical angle [2 Marks]

(iii) Draw a diagram to support your answer in (ii) above. [1 Mark]

(c) Complete the table of the image properties for converging and diverging mirror below

Mirror Object Image

Type Position Position Orientation Size Nature/type
Converging Beyond C Between F Inverted Diminished Real
and C
Converging At C At C Inverted Real
Converging Btw F Inverted Magnified Real
and C
Converging At F Infinity Magnified Real
Converging Btw F Behind the Magnified Virtual
and P mirror
Diverging Any Behind the Erect/ upright Virtual
position mirror
[2 Marks]

PHY 003: ELECTRICITY AND MAGNETISM

5. (a) Define the following terms

(i) Electric Flux (ii) Equipotential surface [2 Marks]

(b) (i) State the condition for resonance in RLC circuits [1 Marks]

(ii) Two charges are located at the positive x- axis of a coordinate system. Charge q1=
2 x 10-9 C is 2 cm from the origin and charge q2= 3 x 10-9 C is 4 cm from the
origin. What is the magnitude of the total force exerted by these two charges on a
charge q3= 5x 10-9C located at the origin? [5 Marks]

(c) Write an expression each for capacitive reactance and inductive reactance. [2 Marks]

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6. (a) (i) State Fleming’s left hand rule

(ii) State two factors upon which the magnitude of a force on a charge moving in a
magnetic field depends on? [3 Marks]

(b) An electron is accelerated by a 5.2 kV potential difference. How strong a magnetic field must be
experienced by the electron if its path is a circle of radius 4 cm? [3 Marks]

(c) A step-up transformer has 240V input which is transformed to 150kV output. The
primary coil has 70 loops and draws a current of 20A when in use.

i. What is the number of loops in the secondary coil?

ii. Calculate the current output. [4 Marks]

PHY 004: MODERN PHYSICS

7. (a) (i) Give one similarity and differentiation each between photoelectric effect and
thermionic effect [2 Marks]

(ii) What is an electron volt? [1 Marks]

(b) A metal has a work function 3.0eV illuminated by light of wavelength 0.6 nm.
Calculate

(i) Threshold frequency [2 Marks]

(ii) Maximum kinetic energy of photo electrons in electron volt [2 Marks]

(c) With a simple sketch, plot a graph of stopping potential against the frequency of
radiation in photoelectric effects. [3 Marks]

8. (a) (i) Differentiate between the hardness of an X-ray and its intensity of radiation

(ii) What is the difference between the Bremsstraulung and the characteristic X-ray
spectrum? [4 Marks]

(b) (i) Show that the Radioactive decay law is given as 𝑁 𝑁 [3 Marks]

(ii) The radioactive isotope Cobalt-57 decays by electron capture with a half-life of
273 days. Calculate its lifetime. [2 Marks]

(c) With relevant formula define the nuclear binding energy. [2 Marks]

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