Practice Post UTME OAU physics 2025 Past Questions

Question 1

A gas is enclosed in a container with a movable piston. The gas is heated from 300 K to 400 K. What is the ratio of the final volume to the initial volume?

A. 1:1

B. 1:2

Correct C. 2:1

D. 3:2

Correct Answer: C

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Question 2

A radioactive sample has a half-life of 10 years. If the initial activity is 100 Bq, what is the activity after 20 years?

A. 10 Bq

B. 20 Bq

Correct C. 50 Bq

D. 100 Bq

Correct Answer: C

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Question 3

A sound wave with a frequency of 200 Hz has a speed of 340 m/s. What is the wavelength of the sound wave?

Correct A. 1.7 m

B. 1.7 cm

C. 1.7 mm

D. 1.7 km

Correct Answer: A

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Question 4

A block of mass 5 kg is attached to a spring with a spring 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. 2 J

B. 5 J

Correct C. 10 J

D. 20 J

Correct Answer: C

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Question 5

A diagram is shown below. What is the force exerted by the spring on the block?

A. 50 N

Correct B. 100 N

C. 150 N

D. 200 N

Correct Answer: B

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Question 6

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 0.1 m, placed in the x-y plane. What is the magnitude of the magnetic moment of the loop?

A. 0.05 A m^2

Correct B. 0.1 A m^2

C. 0.2 A m^2

D. 0.5 A m^2

Correct Answer: B

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Question 7

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 force acting on the particle?

A. 10 N

B. 20 N

Correct C. 30 N

D. 40 N

Correct Answer: C

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Question 8

A block of mass 5 kg is placed on a frictionless surface. A force of 20 N is applied to the block, cau\sing it to accelerate at 2 m/s^2. What is the magnitude of the normal force acting on the block?

A. 10 N

Correct B. 20 N

C. 30 N

D. 40 N

Correct Answer: B

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Question 9

A capacitor of capaci\tance 2 μF is connected to a battery of voltage 10 V. What is the magnitude of the charge stored on the capacitor?

A. 20 μC

Correct B. 40 μC

C. 60 μC

D. 80 μC

Correct Answer: B

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Question 10

A spring of spring cons\tant 100 N/m is stretched by 0.2 m. What is the magnitude of the force exerted by the spring?

A. 10 N

B. 20 N

Correct C. 30 N

D. 40 N

Correct Answer: C

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Question 11

A particle of mass $m$ is attached to a spring with spring cons\tant $k$. The particle is displaced by a dis\tance $x$ from its equilibrium position and released from rest. Assuming the motion is simple harmonic, find the angular frequency $omega$ in terms of $m$ and $k$.

A. 2\sqrt{\frac{k}{m}}

Correct B. \sqrt{\frac{k}{m}}

C. \frac{k}{m}

D. \frac{m}{k}

Correct Answer: B

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Question 12

A light ray passes through a prism with apex angle $A$ and is re\fracted at an angle $\theta$ to the normal. If the angle of incidence is $i$, find the angle of re\fraction $\theta$ in terms of $A$ and $i$.

A. \frac{A}{2} - \frac{i}{2}

Correct B. \frac{A}{2} + \frac{i}{2}

C. \frac{A}{2} - \frac{i}{2}

D. \frac{i}{2} - \frac{A}{2}

Correct Answer: B

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Question 13

A block of mass $m$ is placed on a frictionless surface and attached to a spring with spring cons\tant $k$. The block is displaced by a dis\tance $x$ from its equilibrium position and released from rest. Assuming the motion is simple harmonic, find the force $F$ exerted on the block in terms of $m$ and $k$.

A. kx

Correct B. -kx

C. mx

D. -mx

Correct Answer: B

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Question 14

A light ray passes through a lens with focal length $f$ and is re\fracted at an angle $\theta$ to the normal. If the angle of incidence is $i$, find the angle of re\fraction $\theta$ in terms of $f$ and $i$.

A. \frac{f}{i}

Correct B. \frac{i}{f}

C. \frac{f}{i} + \frac{i}{f}

D. \frac{i}{f} - \frac{f}{i}

Correct Answer: B

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Question 15

A particle of mass $m$ is attached to a spring with spring cons\tant $k$. The particle is displaced by a dis\tance $x$ from its equilibrium position and released from rest. Assuming the motion is simple harmonic, find the potential energy $U$ of the particle in terms of $m$ and $k$.

A. \frac{1}{2}mx^2

Correct B. \frac{1}{2}kx^2

C. \frac{1}{2}mx^2 + \frac{1}{2}kx^2

D. \frac{1}{2}kx^2 - \frac{1}{2}mx^2

Correct Answer: B

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Question 16

A light ray passes from air into a glass slab with re\fractive index 1.5. If the angle of incidence is 30°, find the angle of re\fraction.

Correct A. 20°

B. 30°

C. 40°

D. 50°

Correct Answer: A

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Question 17

A particle of mass 2 kg is attached to a spring with spring cons\tant 100 N/m. If the particle is displaced by 0.2 m from its equilibrium position and released, find its angular frequency.

A. 10 rad/s

Correct B. 20 rad/s

C. 30 rad/s

D. 40 rad/s

Correct Answer: B

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Question 18

A capacitor of capaci\tance 10 μF is charged to a potential difference of 5 V. If a dielectric slab of dielectric cons\tant 2 is inserted between the plates, find the new potential difference.

A. 2.5 V

B. 5 V

Correct C. 7.5 V

D. 10 V

Correct Answer: C

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Question 19

A sound wave with frequency 200 Hz and amplitude 0.1 m is traveling through a medium with speed 340 m/s. If the wave is reflected from a rigid wall, find the intensity of the reflected wave.

A. 10 W/m²

Correct B. 20 W/m²

C. 30 W/m²

D. 40 W/m²

Correct Answer: B

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Question 20

A light ray passes through a convex lens with focal length 20 cm. If the object dis\tance is 30 cm, find the image dis\tance.

A. 10 cm

Correct B. 20 cm

C. 30 cm

D. 40 cm

Correct Answer: B

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Question 21

A gas is enclosed in a container with a movable piston. The gas is heated, cau\sing its temperature to increase. What is the effect on the pressure of the gas?

A. The pressure decreases

Correct B. The pressure increases

C. The pressure remains cons\tant

D. The pressure becomes zero

Correct Answer: B

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Question 22

A sound wave with a frequency of 200 Hz is traveling through a medium. If the speed of the sound wave is 340 m/s, what is the wavelength of the sound wave?

Correct A. 1.7 m

B. 1.7 cm

C. 1.7 km

D. 1.7 μm

Correct Answer: A

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Question 23

A block of mass 5 kg is attached to a horizontal spring with a spring cons\tant of 100 N/m. The block is displaced by 0.2 m from its equilibrium position and released from rest. What is the maximum speed of the block?

A. 0.5 m/s

Correct B. 1.0 m/s

C. 1.5 m/s

D. 2.0 m/s

Correct Answer: B

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Question 24

A capacitor consists of two parallel plates, each with an area of 0.01 m^2. The dis\tance between the plates is 0.001 m. If a potential difference of 10 V is applied across the capacitor, what is the capaci\tance?

Correct A. 10 μF

B. 100 μF

C. 1000 μF

D. 10,000 μF

Correct Answer: A

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Question 25

A \tank contains 1000 kg of water at a temperature of 20°C. If the water is heated to 80°C, what is the change in volume of the water?

A. 0.1 m^3

Correct B. 0.2 m^3

C. 0.3 m^3

D. 0.4 m^3

Correct Answer: B

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