POST UTME NILE UNIVERSITY 2023 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A wave with a frequency of 50 Hz and a wavelength of 0.1 m is traveling through a medium. If the wave is reflected from a fixed \end, what is the magnitude of the displacement of the wave at the fixed \end?
A. 0.01 m
B. 0.02 m
C. 0.03 m
D. 0.04 m
Question 2
A radioactive sample emits \alpha particles with a half-life of 5 days. If the initial activity is 100 Bq, calculate the activity after 10 days.
A. 12.5 Bq
B. 25 Bq
C. 50 Bq
D. 100 Bq
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. What is the magnitude of the centripetal acceleration of the particle?
A. 4 m/s^2
B. 8 m/s^2
C. 12 m/s^2
D. 16 m/s^2
Question 4
A 5 kg block is attached to a horizontal, massless spring with a force cons\tant of 200 N/m. The block is displaced by 2 m from its equilibrium position and released from rest. What is the maximum speed of the block?
A. 2 m/s
B. 4 m/s
C. 6 m/s
D. 8 m/s
Question 5
A particle of mass 0.2 kg is moving in a circular path with a radius of 0.5 m. If the particle has a speed of 2 m/s, what is its kinetic energy?
A. 0.2 J
B. 0.4 J
C. 0.6 J
D. 0.8 J
Question 6
A projectile is launched from the origin with an initial velocity $v_0$ at an angle $\theta$ above the horizontal. If the projectile lands at a dis\tance $R$ from the origin, what is the time of flight?
A. \frac{2R}{v_0 \sin \theta}
B. \frac{R}{v_0 \sin \theta}
C. \frac{R}{v_0 \cos \theta}
D. \frac{2R}{v_0 \cos \theta}
Question 7
A particle of mass $m$ is moving in a circular orbit of radius $R$ under the influence of a central force given by $F(r) = \frac{k}{r^2}$, where $k$ is a cons\tant. If the particle's speed is $v$, what is the magnitude of the force acting on it?
A. \frac{mv^2}{R}
B. \frac{k}{R}
C. \frac{mv^2}{R^2}
D. \frac{k}{R^2}
Question 8
A light ray passes from air into a glass block with a re\fractive index of 1.5. If the angle of incidence is 30°, calculate the angle of re\fraction.
A. 20°
B. 30°
C. 40°
D. 50°
Question 9
A 1000 W heater is connected to a 220 V power source. What is the current flowing through the heater?
A. 3 A
B. 4 A
C. 4.55 A
D. 5 A
Question 10
A vector $mathbf{A}$ has components $A_x = 2$ and $A_y = 3$. If $mathbf{A}$ is rotated by an angle $\theta$ about the $z$-axis, what is the new $x$-component of $mathbf{A}$?
A. \( A_x' = 2 \cos \theta + 3 \sin \theta \)
B. \( A_x' = 2 \sin \theta + 3 \cos \theta \)
C. \( A_x' = 2 \cos \theta - 3 \sin \theta \)
D. \( A_x' = 2 \sin \theta - 3 \cos \theta \)
Question 11
A thermodynamic system is undergoing a process in which the volume is increa\sing while the temperature is cons\tant. If the initial volume is 0.1 m^3 and the final volume is 0.2 m^3, what is the magnitude of the work done by the system?
A. 10 J
B. 20 J
C. 30 J
D. 40 J
Question 12
A simple harmonic oscillator has a mass $m$ and a spring cons\tant $k$. If the oscillator is displaced from its equilibrium position by a dis\tance $x_0$ and released from rest, what is the maximum kinetic energy of the oscillator?
A. \frac{1}{2} k x_0^2
B. \frac{1}{2} m \omega^2 x_0^2
C. \frac{1}{2} m \omega^2 x_0^2 + \frac{1}{2} k x_0^2
D. \frac{1}{2} k x_0^2 + \frac{1}{2} m \omega^2 x_0^2
Question 13
A radioactive sample decays with a half-life of $t_{1/2}$. If the initial activity is $A_0$, what is the activity $A$ after a time $t$?
A. \( A = A_0 e^{-\frac{t}{t_{1/2}}} \)
B. \( A = A_0 e^{\frac{t}{t_{1/2}}} \)
C. \( A = A_0 left\( 1 - e^{-\frac{t}{t_{1/2}}} \right \ \) )
D. \( A = A_0 left\( 1 + e^{-\frac{t}{t_{1/2}}} \right \ \) )
Question 14
A particle of mass 2 kg is moving in a circular path with a radius of 3 m. If the particle has a speed of 4 m/s, calculate the centripetal force acting on the particle.
A. 16 N
B. 32 N
C. 48 N
D. 64 N
Question 15
A projectile is launched from the ground with an initial velocity of 20 m/s at an angle of 30° above the horizontal. If the air resis\tance is negligible, what is the maximum height reached by the projectile?
A. 10 m
B. 15 m
C. 20 m
D. 25 m

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