POST UTME NILE UNIVERSITY 2021 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A gas at 300 K and 1 atm is compressed adiabatically to a pressure of 4 atm. Calculate the final temperature of the gas.
A. 400 K
B. 500 K
C. 600 K
D. 700 K
Question 2
A solid cylindrical rod of radius $r$ and length $L$ is made of a material with Young's modulus $Y$. If a force $F$ is applied \tangentially to the rod, cau\sing it to ext\end by a dis\tance $Delta L$, what is the strain $epsilon$ in terms of $F$, $L$, $r$, and $Y$?
A. \frac{F L}{Y \pi r^2}
B. \frac{F L}{Y r^2}
C. \frac{F L}{Y r}
D. \frac{F L}{Y \pi r}
Question 3
A convex lens of focal length 20 cm is used to form an image of an object placed 30 cm in front of it. Calculate the magnification of the image.
A. 0.5
B. 1
C. 2
D. 3
Question 4
A 100 V AC source is connected to a 10 Ω resistor. If the frequency of the source is 50 Hz, what is the rms value of the current?
A. 5 A
B. 10 A
C. 20 A
D. 50 A
Question 5
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 10 days?
A. 12.5 Bq
B. 25 Bq
C. 50 Bq
D. 100 Bq
Question 6
A block of mass 10 kg is placed on a frictionless surface. A horizontal force of 20 N is applied to the block. What is the acceleration of the block?
A. 2 m/s^2
B. 4 m/s^2
C. 6 m/s^2
D. 8 m/s^2
Question 7
A gas expands from an initial volume of 2 L to a final volume of 5 L against an external pressure of 1 atm. If the gas undergoes an isothermal process, what is the work done by the gas?
A. -10 J
B. -5 J
C. 0 J
D. 5 J
Question 8
A gas is heated from 300 K to 400 K at cons\tant volume. If the initial volume is 2 L, calculate the final volume in L.
A. 1 L
B. 2 L
C. 3 L
D. 4 L
Question 9
A parallel-plate capacitor has a capaci\tance of $C$ and is charged to a potential difference of $V$. If the plates are separated by a dis\tance $d$, what is the energy stored in the capacitor in terms of $C$, $V$, and $d$?
A. \frac{1}{2} C V^2
B. \frac{C V^2}{2 d}
C. \frac{C V^2 d}{2}
D. \frac{C V^2}{d}
Question 10
A uniform magnetic field of magnitude 2 T is directed along the z-axis. A current of 5 A flows in a circular loop of radius 0.2 m, placed in the x-y plane. What is the magnitude of the magnetic moment of the loop?
A. 0.1 A m^2
B. 0.2 A m^2
C. 0.3 A m^2
D. 0.4 A m^2
Question 11
A 2 kg block is moving in a circular path with a radius of 3 m. If the block's velocity is 4 m/s, what is the centripetal acceleration?
A. 0.5 m/s^2
B. 1 m/s^2
C. 2 m/s^2
D. 4 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 force of 12 N, what is the angle between the velocity vector and the radius vector at the ins\tant when the particle is at the top of its circular path?
A. 90°
B. 45°
C. 60°
D. 30°
Question 13
A particle of mass 2 kg is attached to a spring with a spring cons\tant of 100 N/m. The particle is displaced by 0.1 m from its equilibrium position and released from rest. What is the angular frequency of the resulting simple harmonic motion?
A. 10 rad/s
B. 20 rad/s
C. 30 rad/s
D. 40 rad/s
Question 14
A wave has a frequency of 100 Hz and a wavelength of 0.5 m. What is the speed of the wave?
A. 50 m/s
B. 100 m/s
C. 200 m/s
D. 500 m/s
Question 15
A capacitor consists of two parallel plates, each of area 0.1 m^2, separated by a dis\tance of 0.01 m. If the plates are charged to a potential difference of 10 V, what is the capaci\tance?
A. 0.1 F
B. 0.2 F
C. 0.3 F
D. 0.4 F

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