POST UTME ACHIEVERS UNIVERSITY 2020 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A light ray passes through a convex lens of focal length $f$. The object dis\tance is $u$ and the image dis\tance is $v$. The lens equation is given by $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$. If the focal length is doubled and the object dis\tance is halved, what is the new image dis\tance?
A. The image dis\tance is halved
B. The image dis\tance is doubled
C. The image dis\tance remains the same
D. The image dis\tance is quadrupled
Question 2
A projectile is launched from the ground with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If the acceleration due to gravity is 9.8 m/s^2, what is the maximum height reached by the projectile?
A. 10 m
B. 15 m
C. 20 m
D. 25 m
Question 3
A gas is heated from 300 K to 400 K. If the initial volume of the gas is 2 m^3 and the final volume is 3 m^3, what is the magnitude of the work done on the gas?
A. 100 J
B. 200 J
C. 300 J
D. 400 J
Question 4
A particle of mass $m$ is moving in a circular path of radius $r$ with a cons\tant speed $v$. The particle is subject to a centripetal force $F_c$ given by $F_c = \frac{mv^2}{r}$. If the particle's speed is doubled, what happens to the centripetal force?
A. The centripetal force increases by a factor of 2
B. The centripetal force increases by a factor of 4
C. The centripetal force remains the same
D. The centripetal force decreases by a factor of 2
Question 5
A vector has a magnitude of 5 units and makes an angle of 30° with the positive x-axis. If the vector is rotated by 60° in the counterclockwise direction, what is the new magnitude of the vector?
A. 5 units
B. 6 units
C. 7 units
D. 8 units
Question 6
A light ray passes through a convex lens with a focal length of 20 cm. If the object dis\tance is 30 cm, what is the image dis\tance?
A. 10 cm
B. 20 cm
C. 30 cm
D. 40 cm
Question 7
A heat engine operates between a source temperature of 500 K and a \sink temperature of 300 K. If the efficiency of the engine is 30%, what is the maximum possible work output?
A. 1000 J
B. 2000 J
C. 3000 J
D. 4000 J
Question 8
A light ray passes from air into a glass slab of re\fractive index $n$. The angle of incidence is $\theta_i$ and the angle of re\fraction is $\theta_r$. What is the relationship between $\theta_i$ and $\theta_r$?
A. $\theta_i = \theta_r$
B. $\theta_i > \theta_r$
C. $\theta_i < \theta_r$
D. $\theta_i = n\theta_r$
Question 9
A heat engine operates between two temperatures of 500 K and 300 K. If the engine has an efficiency of 30%, what is the magnitude of the work done by the engine?
A. 1000 J
B. 2000 J
C. 3000 J
D. 4000 J
Question 10
A 100 W light bulb is connected to a 220 V power source. What is the current drawn by the bulb?
A. 0.4 A
B. 0.5 A
C. 0.6 A
D. 0.7 A
Question 11
A 10 kg object is moving in a circular path with a cons\tant speed of 5 m/s. What is the magnitude of the centripetal force acting on the object?
A. 25 N
B. 30 N
C. 35 N
D. 40 N
Question 12
A capacitor of capaci\tance 20 μF is connected in parallel with a resistor of resis\tance 30 Ω. If a voltage of 100 V is applied across the circuit, what is the current flowing through the circuit?
A. 3.33 A
B. 6.67 A
C. 10 A
D. 13.33 A
Question 13
A light ray passes through a prism with an angle of incidence of 30° and an angle of re\fraction of 20°. What is the angle of deviation?
A. 10°
B. 20°
C. 30°
D. 40°
Question 14
A light ray passes from air into a glass of re\fractive index 1.5. If the angle of incidence is 30°, calculate the angle of re\fraction.
A. 20°
B. 30°
C. 40°
D. 50°
Question 15
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 angular velocity of the particle?
A. 2 rad/s
B. 4 rad/s
C. 6 rad/s
D. 8 rad/s

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