POST UTME RHEMA UNIVERSITY 2019 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 placed 30 cm away. What is the magnification of the image?
A. 0.5
B. 1
C. 2
D. 3
Question 2
A radioactive sample has a half-life of $T_{1/2}$. If the initial activity is $A_0$, what is the activity after $t$ seconds?
A. A_0 \left\( \frac{1}{2} \right \)^{t/T_{1/2}}
B. A_0 \left\( \frac{1}{2} \right \)^{T_{1/2}/t}
C. A_0 \left\( \frac{1}{2} \right \)^{t/T_{1/2}} + A_0
D. A_0 \left\( \frac{1}{2} \right \)^{t/T_{1/2}} - A_0
Question 3
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 subjected to a centripetal acceleration of 2 m/s^2, what is the magnitude of the force acting on the particle?
A. 8 N
B. 10 N
C. 12 N
D. 16 N
Question 4
A sound wave has a frequency of 200 Hz and a wavelength of 0.5 m. What is the speed of the sound wave?
A. 100 m/s
B. 200 m/s
C. 300 m/s
D. 400 m/s
Question 5
A circuit consists of a resistor, an inductor, and a capacitor connected in series. If the resis\tance is 10Ω, the induc\tance is 5H, and the capaci\tance is 0.1F, what is the impedance of the circuit at a frequency of 50Hz?
A. 20Ω
B. 30Ω
C. 40Ω
D. 50Ω
Question 6
A gas is enclosed in a container at a pressure of 2.5 atm and a temperature of 300 K. If the pressure is increased to 4.0 atm while keeping the temperature cons\tant, what is the new volume of the gas?
A. \( 2.00 \text{ L} \)
B. \( 3.00 \text{ L} \)
C. \( 4.00 \text{ L} \)
D. \( 5.00 \text{ L} \)
Question 7
A simple harmonic motion has a frequency of $f$ and an amplitude of $A$. If the time period is doubled, what is the new amplitude?
A. A/2
B. A
C. 2A
D. A \left\( \frac{1}{2} \right \)^{1/2}
Question 8
A particle of mass $m$ is moving in a circular path of radius $r$ with a cons\tant speed $v$. Find the magnitude of the force $F$ exerted on the particle by the centripetal force.
A. \frac{mv^2}{r}
B. \frac{mr^2}{v^2}
C. \frac{v^2}{mr}
D. \frac{r^2}{mv^2}
Question 9
A 50 kg person is s\tanding on a spring scale in an elevator. If the elevator accelerates upward at 2 m/s², what is the reading on the spring scale?
A. 50 kg
B. 55 kg
C. 60 kg
D. 65 kg
Question 10
A projectile is launched from the ground with an initial velocity $v_0$ at an angle $\theta$ above the horizontal. Find the time $t$ it takes for the projectile to reach its maximum height.
A. \frac{v_0 \sin \theta}{g}
B. \frac{v_0 \cos \theta}{g}
C. \frac{v_0 \sin \theta}{2g}
D. \frac{v_0 \cos \theta}{2g}
Question 11
A sound wave with a frequency of 200Hz is traveling through a medium with a speed of 340m/s. If the wavelength of the sound wave is 1.7m, what is the amplitude of the sound wave?
A. 0.1m
B. 0.2m
C. 0.3m
D. 0.4m
Question 12
A circuit consists of a 12 V battery, a 4 Ω resistor, and a 6 Ω resistor connected in series. If the current in the circuit is 0.5 A, what is the total resis\tance of the circuit?
A. \( 10 \text{ Ω} \)
B. \( 12 \text{ Ω} \)
C. \( 14 \text{ Ω} \)
D. \( 16 \text{ Ω} \)
Question 13
A 5.0 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. The block is displaced by 2.0 m from its equilibrium position and released from rest. What is the maximum speed of the block?
A. 2.0 m/s
B. 4.0 m/s
C. 6.0 m/s
D. 8.0 m/s
Question 14
A charged particle moves through a magnetic field with a velocity of \( 2.5 \times 10^6 \text{ m/s} \) and a charge of \( 1.6 \times 10^{-19} \text{ C} \). If the magnetic field strength is \( 0.5 \text{ T} \), what is the force experienced by the particle?
A. \( 2.0 \times 10^{-14} \text{ N} \)
B. \( 4.0 \times 10^{-14} \text{ N} \)
C. \( 6.0 \times 10^{-14} \text{ N} \)
D. \( 8.0 \times 10^{-14} \text{ N} \)
Question 15
A 10 μF capacitor is connected in series with a 20 Ω resistor and a 120 V AC source. If the frequency of the AC source is 50 Hz, what is the impedance of the circuit?
A. 20 Ω
B. 40 Ω
C. 60 Ω
D. 80 Ω

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