POST UTME IGBINEDION UNIVERSITY 2021 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A convex lens of focal length 20 cm forms an image of an object at a dis\tance of 30 cm from the lens. What is the magnification of the lens?
A. -0.5
B. -1.0
C. -1.5
D. -2.0
Question 2
A parallel plate capacitor has plates of area 0.04 m^2 and separation 3 mm. If the dielectric cons\tant of the material between the plates is 3.2, calculate the capaci\tance.
A. 2.5 μF
B. 5.0 μF
C. 10.0 μF
D. 20.0 μF
Question 3
A block of mass 5 kg is attached to a spring with a spring cons\tant of 200 N/m. If the block is displaced by 0.2 m from its equilibrium position, calculate the force exerted by the spring on the block.
A. 40 N
B. 80 N
C. 120 N
D. 160 N
Question 4
A parallel plate capacitor has a capaci\tance of 10 μF and a plate separation of 2 mm. If the dielectric cons\tant of the material between the plates is 3, what is the electric field between the plates?
A. 1000 V/m
B. 2000 V/m
C. 3000 V/m
D. 4000 V/m
Question 5
A photon of energy $E$ is incident on a metal surface. The work function of the metal is $W$. Find the maximum kinetic energy $K_{max}$ of the photoelectrons emitted.
A. K_{max} = E + W
B. K_{max} = E - W
C. K_{max} = W - E
D. K_{max} = E \cdot W
Question 6
A particle of mass 2 kg is moving in a circular path of radius 3 m with a speed of 4 m/s. What is the magnitude of the centripetal force acting on the particle?
A. 10 N
B. 20 N
C. 30 N
D. 40 N
Question 7
A heat engine operates between two reservoirs at temperatures 500 K and 300 K. If the engine produces 100 J of work per cycle, what is the efficiency of the engine?
A. 20%
B. 30%
C. 40%
D. 50%
Question 8
A parallel plate capacitor consists of two plates of area $A$ separated by a dis\tance $d$. The capaci\tance of the capacitor is given by $C = \frac{epsilon_0 A}{d}$. If the area of the plates is doubled and the dis\tance between them is halved, what is the new capaci\tance?
A. \frac{\epsilon_0 A}{d}
B. \frac{2\epsilon_0 A}{d}
C. \frac{\epsilon_0 (2A)}{d}
D. \frac{2\epsilon_0 A}{d/2}
Question 9
A circuit consists of a 12 V battery, a 4 Ω resistor, and a capacitor with capaci\tance $C$. The circuit is connected to a switch that is initially open. At $t = 0$, the switch is closed. Find the charge $Q(t)$ on the capacitor at time $t$.
A. Q(t) = C \cdot 12 \left\( 1 - e^{-\frac{t}{RC}} \right \)
B. Q(t) = C \cdot 12 \left\( 1 + e^{-\frac{t}{RC}} \right \)
C. Q(t) = C \cdot 12 \left\( 1 - e^{\frac{t}{RC}} \right \)
D. Q(t) = C \cdot 12 \left\( 1 + e^{\frac{t}{RC}} \right \)
Question 10
A photon of energy $E$ is incident on a metal surface. If the work function of the metal is $\phi$, what is the maximum kinetic energy of the photoelectron?
A. E - \phi
B. E + \phi
C. \phi - E
D. \phi + E
Question 11
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 $m$, $k$, and $x_0$.
A. \omega = \frac{k}{m}
B. \omega = \sqrt{\frac{k}{m}}
C. \omega = \frac{m}{k}
D. \omega = \frac{x_0}{m}
Question 12
A gas expands from 1.5 L to 3 L against a cons\tant external pressure of 2 atm. If the initial temperature is 300 K, calculate the work done by the gas.
A. 120 J
B. 240 J
C. 360 J
D. 480 J
Question 13
A magnetic field of 0.5 T is directed perp\endicular to a current-carrying wire of length 2 m. If the current in the wire is 5 A, what is the magnitude of the force exerted on the wire?
A. 0.5 N
B. 1 N
C. 2 N
D. 5 N
Question 14
A particle of mass 2 kg is moving in a circular path of radius 3 m with a cons\tant speed of 4 m/s. If the particle is subject to a centripetal force of 12 N, what is the magnitude of the acceleration of the particle?
A. 8 m/s^2
B. 12 m/s^2
C. 16 m/s^2
D. 24 m/s^2
Question 15
A beam of light passes from air into a glass of re\fractive index 1.5. If the angle of incidence is 30°, what is the angle of re\fraction?
A. 20°
B. 25°
C. 30°
D. 35°

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