POST UTME CRAWFORD UNIVERSITY 2021 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A parallel plate capacitor has a capaci\tance of 10 μF and is charged to a potential difference of 10 V. If a dielectric material with a dielectric cons\tant of 2 is inserted between the plates, what is the new capaci\tance?
A. 20 μF
B. 30 μF
C. 40 μF
D. 50 μF
Question 2
A 10 μF capacitor is connected in series with a 20 Ω resistor and a 50 V battery. What is the current flowing through the circuit?
A. 1 A
B. 2 A
C. 2.5 A
D. 3 A
Question 3
A resistor of 10 ohms is connected in series with a capacitor of 100 microfarads. If the voltage across the resistor is 10 V, what is the current flowing through the circuit?
A. 0.1 A
B. 0.2 A
C. 0.3 A
D. 0.4 A
Question 4
A radioactive sample of Uranium-238 undergoes \alpha decay, emitting an \alpha particle with a mass of 4 u and a charge of +2e. If the initial mass of the Uranium-238 nucleus is 238 u, what is the mass of the resulting nucleus after the decay?
A. 234 u
B. 236 u
C. 238 u
D. 240 u
Question 5
A charged particle moves in a uniform magnetic field. If the particle has a charge of +2e and a velocity of 3 × 10^6 m/s, what is the radius of the circular path?
A. 1.5 m
B. 3 m
C. 4.5 m
D. 6 m
Question 6
A beam of light is incident on a glass surface at an angle of 45°. If the re\fractive index of glass is 1.5, calculate the angle of re\fraction u\sing Snell's law.
A. 30°
B. 45°
C. 60°
D. 75°
Question 7
A 5 kg block of ice at 0°C is placed in a 10°C water bath. Assuming the specific heat capacity of water is 4.184 J/g°C, what is the mass of water that needs to be heated to 10°C to melt the ice completely?
A. 1.25 kg
B. 2.5 kg
C. 3.75 kg
D. 5 kg
Question 8
A 2 kg block is attached to a horizontal spring with a spring cons\tant of 100 N/m. If the block is displaced by 0.5 m from its equilibrium position and released, what is the maximum speed of the block?
A. 1.414 m/s
B. 2.828 m/s
C. 4.242 m/s
D. 5.657 m/s
Question 9
A 2.0 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. The block is displaced by 0.20 m from its equilibrium position and released from rest. What is the maximum speed of the block?
A. 0.20 m/s
B. 0.20 m/s
C. 0.20 m/s
D. 0.20 m/s
Question 10
A sound wave with a frequency of 200 Hz and an amplitude of 0.5 m is traveling through a medium with a speed of 343 m/s. If the wave is reflected off a wall, what is the frequency of the reflected wave?
A. 200 Hz
B. 400 Hz
C. 600 Hz
D. 800 Hz
Question 11
A capacitor has a capaci\tance of 10 μF and is charged to a potential difference of 5 V. If the capacitor is connected to a resistor with a resis\tance of 100 Ω, what is the time cons\tant of the circuit?
A. 0.1 s
B. 0.5 s
C. 1.0 s
D. 2.0 s
Question 12
A particle of mass 0.1 kg is moving in a circular path with a radius of 0.2 m. If the particle's velocity is 5 m/s, what is the magnitude of the centripetal force acting on the particle?
A. 0.5 N
B. 1 N
C. 2 N
D. 3 N
Question 13
A gas expands from 1 L to 2 L against a cons\tant external pressure of 2 atm. Calculate the work done by the gas.
A. 4 J
B. 8 J
C. 16 J
D. 32 J
Question 14
A circuit consists of a 12 V battery, a 4 Ω resistor, and a 6 Ω resistor connected in series. What is the total resis\tance of the circuit?
A. 10 Ω
B. 12 Ω
C. 16 Ω
D. 20 Ω
Question 15
A thermodynamic system undergoes a process from an initial state (i) to a final state (f). If the system's internal energy (U) is 100 J at state (i) and 120 J at state (f), and the work done (W) on the system is 20 J, what is the change in the system's entropy (ΔS)?
A. 0.5 J/K
B. 1 J/K
C. 2 J/K
D. 3 J/K

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