POST UTME RHEMA UNIVERSITY 2020 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A circuit consists of a battery, a resistor, and a capacitor in series. If the capacitor is fully charged, what will happen to the current in the circuit?
A. The current will increase.
B. The current will decrease.
C. The current will remain cons\tant.
D. The current will become zero.
Question 2
A 2 m long p\endulum is released from an initial angle of 30°. If the p\endulum is released from rest, calculate the time period of the p\endulum.
A. 1 s
B. 2 s
C. 3 s
D. 4 s
Question 3
A coil of wire of radius $r$ and resis\tance $R$ is connected to a battery of emf $\mathcal{E}$ through a switch. Calculate the current $I$ in the coil at time $t$ after the switch is closed.
A. I = \frac{\mathcal{E}}{R}\( 1 - e^{-t/RC} \)
B. I = \frac{\mathcal{E}}{R}\( 1 + e^{-t/RC} \)
C. I = \frac{\mathcal{E}}{R}\( e^{-t/RC} - 1 \)
D. I = \frac{\mathcal{E}}{R}\( e^{t/RC} - 1 \)
Question 4
A particle of mass 1 kg is moving in a straight line with a speed of 4 m/s. If the particle is subject to a force of 10 N, calculate the acceleration of the particle.
A. 2 m/s^2
B. 4 m/s^2
C. 6 m/s^2
D. 8 m/s^2
Question 5
A radioactive sample decays according to the equation $N(t) = N_0 e^{-\lambda t}$, where $N_0$ is the initial number of nuclei, $\lambda$ is the decay cons\tant, and $t$ is time. If the sample decays to $\frac{1}{4}$ of its initial value in 10 minutes, what is the decay cons\tant?
A. \frac{1}{10} \text{min}^{-1}
B. \frac{1}{20} \text{min}^{-1}
C. \frac{1}{30} \text{min}^{-1}
D. \frac{1}{40} \text{min}^{-1}
Question 6
A circuit consists of a resistor of 10 Ω and an inductor of 5 H in series. If the circuit is connected to a voltage source of 20 V, what is the current in the circuit?
A. 0.5 A
B. 1.0 A
C. 1.5 A
D. 2.0 A
Question 7
A 5 Ω resistor is connected in series with a 10 Ω resistor and a 20 Ω resistor. If a 10 V DC source is connected across the circuit, calculate the current flowing through the 5 Ω resistor.
A. 0.5 A
B. 1 A
C. 1.5 A
D. 2 A
Question 8
A radioactive sample emits \alpha particles with a half-life of 5 days. If the initial activity is 100 Bq, what is the activity after 15 days?
A. 12.5 Bq
B. 25 Bq
C. 50 Bq
D. 100 Bq
Question 9
A beam of light of wavelength $\lambda$ is incident on a \single slit of width $a$. The screen is placed at a dis\tance $D$ from the slit. Calculate the angle $\theta$ at which the first minimum occurs.
A. \sin \theta = \frac{\lambda}{a}
B. \sin \theta = \frac{\lambda}{D}
C. \sin \theta = \frac{a}{D}
D. \sin \theta = \frac{\lambda D}{a}
Question 10
A sound wave with a frequency of 200 Hz is traveling through a medium with a speed of 340 m/s. What is the wavelength of the sound wave?
A. 1.7 m
B. 1.7 cm
C. 1.7 km
D. 1.7 μm
Question 11
A particle of mass 2 kg is moving in a circular orbit of radius 1 m with a speed of 3 m/s. If the particle is subject to a centripetal force of 10 N, calculate the magnitude of the acceleration of the particle.
A. 3 m/s^2
B. 6 m/s^2
C. 9 m/s^2
D. 12 m/s^2
Question 12
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 net force acting on the particle?
A. 8 N
B. 12 N
C. 16 N
D. 20 N
Question 13
A projectile is launched from the ground with an initial velocity $v_0$ at an angle $\theta$ above the horizontal. If the projectile lands at a dis\tance $R$ from the launch point, what is the range of the projectile?
A. \frac{v_0^2 \sin\( 2\theta \)}{g}
B. \frac{v_0^2 \sin\( \theta \)}{g}
C. \frac{v_0^2 \cos\( \theta \)}{g}
D. \frac{v_0^2 \sin\( \theta \)}{2g}
Question 14
A block of mass 2 kg is attached to a 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, calculate the maximum velocity of the block.
A. 1 m/s
B. 2 m/s
C. 3 m/s
D. 4 m/s
Question 15
A wave has a frequency of 50 Hz and a wavelength of 0.1 m. Calculate the speed of the wave.
A. 5 m/s
B. 10 m/s
C. 20 m/s
D. 50 m/s

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