Practice Post UTME ACHIEVERS UNIVERSITY physics 2021 Past Questions

Question 1 View Details

A 2.5 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. The block is displaced by 0.2 m from its equilibrium position and released from rest. Assuming the block undergoes simple harmonic motion, calculate the maximum speed of the block as it passes through the equilibrium position.

A. 2.5 m/s

Correct B. 5.0 m/s

C. 7.5 m/s

D. 10.0 m/s

Correct Answer: B

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Question 2 View Details

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

Correct B. 0.4 A

C. 0.6 A

D. 0.8 A

Correct Answer: B

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Question 3 View Details

A 5 kg block is moving in a circular path with a radius of 2 m. If the block experiences a centripetal acceleration of 4 m/s^2, what is the speed of the block?

A. 2 m/s

B. 4 m/s

Correct C. 6 m/s

D. 8 m/s

Correct Answer: C

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Question 4 View Details

A 1000 Hz AC voltage source is connected in series with a 20 Ω resistor and a 10 μF capacitor. If the voltage source has a maximum voltage of 20 V, what is the maximum current flowing through the circuit?

A. 0.1 A

Correct B. 0.2 A

C. 0.3 A

D. 0.4 A

Correct Answer: B

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Question 5 View Details

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?

Correct A. 0 N

B. 2 N

C. 4 N

D. 6 N

Correct Answer: A

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Question 6 View Details

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. 8 N

B. 16 N

Correct C. 32 N

D. 64 N

Correct Answer: C

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Question 7 View Details

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

Correct C. 30 cm

D. 40 cm

Correct Answer: C

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Question 8 View Details

A body of mass 5 kg is moving with a velocity of 10 m/s. What is its kinetic energy?

A. 250 J

Correct B. 500 J

C. 750 J

D. 1000 J

Correct Answer: B

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Question 9 View Details

A light ray passes from air into a glass of re\fractive index 1.5. What is the angle of re\fraction?

A. 30°

Correct B. 45°

C. 60°

D. 75°

Correct Answer: B

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Question 10 View Details

A spring of spring cons\tant 100 N/m is stretched by 2 m. What is the work done?

A. 100 J

B. 200 J

Correct C. 300 J

D. 400 J

Correct Answer: C

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Question 11 View Details

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 magnitude of the acceleration of the particle?

A. 16 m/s^2

B. 20 m/s^2

Correct C. 24 m/s^2

D. 28 m/s^2

Correct Answer: C

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Question 12 View Details

A parallel plate capacitor has a capaci\tance of 5 μF and is charged to a potential difference of 10 V. If the plates are separated by a dis\tance of 2 mm, what is the surface charge density on the plates?

A. 2.5 C/m^2

Correct B. 5 C/m^2

C. 10 C/m^2

D. 20 C/m^2

Correct Answer: B

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Question 13 View Details

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?

Correct A. 25 Bq

B. 50 Bq

C. 75 Bq

D. 100 Bq

Correct Answer: A

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Question 14 View Details

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?

Correct A. Positive x-direction

B. Negative x-direction

C. Positive y-direction

D. Negative y-direction

Correct Answer: A

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Question 15 View Details

A particle of mass 1 kg is moving in a circular path of radius 1 m with a cons\tant speed of 5 m/s. If the particle is subjected to a centripetal force of 20 N, what is the magnitude of the acceleration of the particle?

A. 25 m/s^2

B. 30 m/s^2

C. 35 m/s^2

Correct D. 40 m/s^2

Correct Answer: D

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Question 16 View Details

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

Correct B. 10 C/m^2

C. 15 C/m^2

D. 20 C/m^2

Correct Answer: B

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Question 17 View Details

A radioactive sample has an initial activity of 200 Bq. If the half-life of the sample is 3 hours, what is the activity of the sample after 6 hours?

A. 50 Bq

B. 100 Bq

Correct C. 150 Bq

D. 200 Bq

Correct Answer: C

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Question 18 View Details

A wave has a frequency of 100 Hz and a wavelength of 1 m. If the wave is traveling in the positive x-direction, what is the direction of the wave's velocity?

Correct A. Positive x-direction

B. Negative x-direction

C. Positive y-direction

D. Negative y-direction

Correct Answer: A

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Question 19 View Details

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 magnitude of the acceleration of the particle?

Correct A. 6 m/s^2

B. 12 m/s^2

C. 18 m/s^2

D. 24 m/s^2

Correct Answer: A

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Question 20 View Details

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

Correct B. 250 J

C. 375 J

D. 500 J

Correct Answer: B

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Question 21 View Details

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?

Correct A. 12.5 g

B. 25 g

C. 50 g

D. 100 g

Correct Answer: A

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Question 22 View Details

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%

Correct B. 25%

C. 30%

D. 35%

Correct Answer: B

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Question 23 View Details

A particle of mass 3 kg is moving in a circular path of radius 4 m with a cons\tant speed of 5 m/s. If the particle is subjected to a centripetal force of 15 N, what is the magnitude of the acceleration of the particle?

Correct A. 5 m/s^2

B. 10 m/s^2

C. 15 m/s^2

D. 20 m/s^2

Correct Answer: A

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Question 24 View Details

A body of mass 4 kg is moving with a velocity of 8 m/s. If it is subjected to a force of 24 N, what is the change in its kinetic energy?

A. 64 J

Correct B. 128 J

C. 192 J

D. 256 J

Correct Answer: B

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Question 25 View Details

A radioactive subs\tance has a half-life of 3 years. If 150 g of the subs\tance is initially present, how much of the subs\tance will remain after 9 years?

Correct A. 6.25 g

B. 12.5 g

C. 25 g

D. 50 g

Correct Answer: A

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