POST UTME GREENFIELD UNIVERSITY 2017 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A heat engine operates between a high-temperature reservoir at 500 K and a low-temperature reservoir at 300 K. What is the maximum efficiency?
A. 0.25
B. 0.30
C. 0.35
D. 0.40
Question 2
A wave with a frequency of 50 Hz and a wavelength of 2 m is traveling through a medium. If the wave is reflected from a fixed \end, determine the phase difference between the incident and reflected waves.
A. 0
B. \pi
C. 2\pi
D. 3\pi
Question 3
A vector has a magnitude of 5 units and makes an angle of 60° with the positive x-axis. What is the x-component of the vector?
A. 2.5 units
B. 3.5 units
C. 4.5 units
D. 5.5 units
Question 4
A magnetic field $\vec{B}$ is directed perp\endicular to the plane of a circular loop of wire with radius $r$. The loop carries a current $I$ and is placed in the magnetic field. Find the magnitude of the magnetic force $\vec{F}$ on the loop due to the magnetic field.
A. F = IBl
B. F = \frac{I}{B}l
C. F = Bl
D. F = \frac{Bl}{I}
Question 5
A light ray passes from air into a glass block with a re\fractive index of 1.5. If the angle of incidence is 30°, determine the angle of re\fraction.
A. 20°
B. 30°
C. 40°
D. 50°
Question 6
A particle of mass $m$ is attached to a spring with spring cons\tant $k$. The particle is displaced from its equilibrium position by a dis\tance $x_0$ and released from rest. Assuming the motion is simple harmonic, find the angular frequency $omega$ in terms of $k$ and $m$.
A. \omega = \frac{k}{m}
B. \omega = \sqrt{\frac{k}{m}}
C. \omega = \frac{m}{k}
D. \omega = \frac{1}{\sqrt{km}}
Question 7
A light ray passes from air into a glass of re\fractive index 1.5. If the angle of incidence is 30°, calculate the angle of re\fraction.
A. 20°
B. 30°
C. 40°
D. 50°
Question 8
A lens of focal length 20 cm is used to form an image of an object 30 cm away. If the object is moved 10 cm closer to the lens, determine the new image dis\tance.
A. 10 cm
B. 20 cm
C. 30 cm
D. 40 cm
Question 9
A particle of mass $m$ is moving in a straight line with an initial velocity $v_0$ and is subjected to a cons\tant acceleration $a$. If the particle's velocity after time $t$ is given by $v = v_0 + at$, what is the particle's position after time $t$?
A. \frac{1}{2}at^2 + v_0t
B. v_0t + at
C. \frac{1}{2}v_0t^2 + at
D. \frac{1}{2}at^2 - v_0t
Question 10
A parallel plate capacitor has a capaci\tance of $C = 2\,\mu\text{F}$ and is charged to a potential difference of $V = 10\,\text{V}$. If the dis\tance between the plates is doubled, what is the new capaci\tance $C'$?
A. 4\,\mu\text{F}
B. 2\,\mu\text{F}
C. 1\,\mu\text{F}
D. 0.5\,\mu\text{F}
Question 11
A block of mass $M$ and density $\rho$ is floating in a fluid of density $\rho_f$. If the block is displaced by a dis\tance $x$ from its equilibrium position, what is the magnitude of the restoring force acting on it?
A. \frac{\rho V g x}{\rho_f}
B. \frac{\rho V g x}{\rho}
C. \frac{\rho_f V g x}{\rho}
D. \frac{\rho V g x}{\rho V}
Question 12
A 100 W light bulb is connected to a 220 V power source. What is the current flowing through the bulb?
A. 0.45 A
B. 0.9 A
C. 1.8 A
D. 4.5 A
Question 13
A thermodynamic system is undergoing a process in which its entropy is increa\sing. If the system is in contact with a heat reservoir at temperature $T$, what is the direction of heat flow?
A. Heat flows from the system to the reservoir
B. Heat flows from the reservoir to the system
C. Heat flows in both directions
D. Heat flow is zero
Question 14
A 100 W light bulb is connected to a 220 V power source. What is the current drawn?
A. 0.5 A
B. 1 A
C. 2 A
D. 3 A
Question 15
A particle of mass 2 kg is attached to a spring with a spring cons\tant of 100 N/m. If the particle is displaced by 0.5 m from its equilibrium position and released from rest, determine the angular frequency of the simple harmonic motion.
A. 1 rad/s
B. 10 rad/s
C. 20 rad/s
D. 50 rad/s

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