POST UTME LEAD CITY UNIVERSITY 2023 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A magnetic field is produced by a current-carrying wire. If the current is increased by a factor of $n$, what happens to the magnetic field?
A. Increases by a factor of $n$
B. Decreases by a factor of $n$
C. Increases by a factor of $n^2$
D. Decreases by a factor of $n^2$
Question 2
A heat engine operates between two temperatures, 300 K and 400 K. If the engine has an efficiency of 30%, what is the temperature of the hot reservoir?
A. 350 K
B. 400 K
C. 450 K
D. 500 K
Question 3
A heat engine operates between two temperatures $T_1$ and $T_2$, where $T_1 > T_2$. The engine has an efficiency of $\eta = 1 - \frac{T_2}{T_1}$. What is the maximum possible efficiency of the engine?
A. 1 - \frac{T_2}{T_1}
B. 1 - \frac{T_1}{T_2}
C. \frac{T_1 - T_2}{T_1}
D. \frac{T_2 - T_1}{T_2}
Question 4
A uniform solid sphere of radius R and mass M is placed in a container filled with a fluid of density ρ. The sphere is partially submerged in the fluid, with a volume V submerged. What is the pressure at the bottom of the sphere?
A. ρgV
B. ρg\( R^3 - V \)
C. ρg\( R^3 - V \)/V
D. ρg\( R^3 - V \)/R
Question 5
A block of mass 5 kg is attached to a horizontal spring with a spring cons\tant of 200 N/m. If the block is displaced by 0.2 m from its equilibrium position and released, what is the maximum speed of the block?
A. 2 m/s
B. 3 m/s
C. 4 m/s
D. 5 m/s
Question 6
A particle of mass $m$ and charge $q$ is moving in a circular path of radius $R$ in a uniform magnetic field of strength $B$. If the particle's velocity is $v$, what is the magnitude of the magnetic force acting on it?
A. \frac{mv^2}{R}
B. \frac{mv^2}{2R}
C. \frac{mv^2}{4R}
D. \frac{mv^2}{8R}
Question 7
A charged particle of mass 1.5 kg and charge 3 C is moving in a magnetic field of strength 2 T. If the particle is moving with a speed of 5 m/s, what is the magnitude of the force acting on the particle?
A. 0.15 N
B. 0.30 N
C. 0.45 N
D. 0.60 N
Question 8
A 10 μF capacitor is connected in series with a 20 Ω resistor and a 120 V AC source. Determine the impedance of the circuit.
A. 15 Ω
B. 20 Ω
C. 25 Ω
D. 30 Ω
Question 9
A 5 kg block is moving with a velocity of 2 m/s on a frictionless surface. If a force of 10 N is applied to the block, what is the acceleration of the block?
A. 0.5 m/s²
B. 1.0 m/s²
C. 1.5 m/s²
D. 2.0 m/s²
Question 10
A gas is compressed from an initial volume of 2.0 m^3 to a final volume of 1.0 m^3 at a cons\tant temperature of 300 K. What is the work done on the gas?
A. 2000 J
B. 4000 J
C. 6000 J
D. 8000 J
Question 11
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 ejected electron?
A. E - \phi
B. E + \phi
C. \phi - E
D. E + 2\phi
Question 12
A sound wave has a frequency of $f$ and a speed of $v$. What is the wavelength of the wave?
A. \frac{v}{f}
B. \frac{f}{v}
C. \frac{v^2}{f}
D. \frac{f^2}{v}
Question 13
A circuit consists of a 10 Ω resistor and a 20 μF capacitor connected in series. If a voltage of 100 V is applied across the circuit, what is the time cons\tant of the circuit?
A. 0.2 s
B. 0.5 s
C. 1 s
D. 2 s
Question 14
A 2.5 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. The block is displaced by 0.15 m from its equilibrium position and released from rest. Assuming the block undergoes simple harmonic motion, determine the maximum speed of the block.
A. 0.75 m/s
B. 1.25 m/s
C. 1.5 m/s
D. 2.0 m/s
Question 15
A gas is enclosed in a container with a movable piston. The gas is heated at cons\tant pressure, cau\sing its volume to increase. Which of the following statements is true about the change in internal energy of the gas?
A. The internal energy increases
B. The internal energy decreases
C. The internal energy remains cons\tant
D. The internal energy increases or decreases dep\ending on the specific gas

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