POST UTME ACHIEVERS UNIVERSITY 2021 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1000 Ω resistor, a 2000 Ω resistor, and a 3000 Ω resistor are connected in series across a 12 V battery. U\sing Kirchhoff's voltage law, calculate the current flowing through the 1000 Ω resistor.
A. 0.5 A
B. 1.0 A
C. 1.5 A
D. 2.0 A
Question 2
A wave has a frequency of 50 Hz and a wavelength of 2 m. If the wave is traveling in the positive x-direction, what is the direction of the wave's velocity?
A. Positive x-direction
B. Negative x-direction
C. Positive y-direction
D. Negative y-direction
Question 3
A convex lens of focal length 20 cm is placed in contact with a concave lens of focal length -15 cm. What is the focal length of the combination?
A. 10 cm
B. 20 cm
C. 30 cm
D. 40 cm
Question 4
A heat engine operates between a high-temperature reservoir at 500 K and a low-temperature reservoir at 300 K. The engine has an efficiency of 30%. Calculate the maximum possible work output of the engine.
A. 100 J
B. 200 J
C. 300 J
D. 400 J
Question 5
A radioactive sample has an initial activity of 100 Bq. If the half-life of the sample is 2 hours, what is the activity of the sample after 4 hours?
A. 25 Bq
B. 50 Bq
C. 75 Bq
D. 100 Bq
Question 6
A 100 V AC supply is connected to a 50 Ω resistor. Calculate the rms value of the current flowing through the resistor.
A. 2 A
B. 4 A
C. 6 A
D. 8 A
Question 7
A heat engine operates between the temperatures 400 K and 500 K. If it absorbs 1500 J of heat from the high-temperature reservoir, what is the efficiency of the engine?
A. 15%
B. 20%
C. 25%
D. 30%
Question 8
A 10 Ω resistor is connected in series with a 20 Ω resistor and a 30 Ω resistor. If a 12 V battery is connected across the circuit, what is the current flowing through the 20 Ω resistor?
A. 0.2 A
B. 0.4 A
C. 0.6 A
D. 0.8 A
Question 9
A 2 kg block is placed on a frictionless surface and a horizontal force of 10 N is applied to it. If the block accelerates at 2 m/s^2, what is the force of friction acting on the block?
A. 0 N
B. 2 N
C. 4 N
D. 6 N
Question 10
A parallel plate capacitor has a capaci\tance of 10 μF and is charged to a potential difference of 20 V. If the plates are separated by a dis\tance of 4 mm, what is the surface charge density on the plates?
A. 5 C/m^2
B. 10 C/m^2
C. 15 C/m^2
D. 20 C/m^2
Question 11
A radioactive subs\tance has a half-life of 2 years. If 100 g of the subs\tance is initially present, how much of the subs\tance will remain after 6 years?
A. 12.5 g
B. 25 g
C. 50 g
D. 100 g
Question 12
A body of mass 5 kg is moving with a velocity of 10 m/s. If it is subjected to a force of 20 N, what is the change in its kinetic energy?
A. 125 J
B. 250 J
C. 375 J
D. 500 J
Question 13
A light ray passes from air into a glass of re\fractive index 1.5. What is the angle of re\fraction?
A. 30°
B. 45°
C. 60°
D. 75°
Question 14
A heat engine operates between the temperatures 300 K and 400 K. If it absorbs 1000 J of heat from the high-temperature reservoir, what is the efficiency of the engine?
A. 20%
B. 25%
C. 30%
D. 35%
Question 15
A block of mass 5 kg is attached to a horizontal spring with a force cons\tant of 100 N/m. If the block is displaced by 0.2 m from its equilibrium position, what is the potential energy stored in the spring?
A. 1 J
B. 2 J
C. 3 J
D. 4 J

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: