Practice Post UTME REDEEMERS UNIVERSITY physics 2020 Past Questions

Question 1

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

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 2

A circuit consists of a 12 V battery, a 4 Ω resistor, and a 2 Ω resistor connected in series. What is the current flowing through the 2 Ω resistor?

A. 1 A

Correct B. 2 A

C. 3 A

D. 4 A

Correct Answer: B

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Question 3

A projectile is launched from the ground with an initial velocity of 20 m/s at an angle of 60° above the horizontal. What is the maximum height reached by the projectile?

A. 10 m

B. 15 m

Correct C. 20 m

D. 25 m

Correct Answer: C

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Question 4

A nucleus of mass number 238 has an atomic number of 92. What is the number of protons in the nucleus?

A. 90

Correct B. 92

C. 94

D. 96

Correct Answer: B

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Question 5

A 100 Ω resistor is connected in parallel with a 200 Ω resistor. What is the equivalent resis\tance of the circuit?

A. 50 Ω

Correct B. 66.67 Ω

C. 100 Ω

D. 200 Ω

Correct Answer: B

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Question 6

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 from rest, calculate the maximum velocity of the particle.

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 7

A block of wood is floating in a \tank of water. If the block has a volume of 0.5 m^3 and a mass of 50 kg, calculate the buoyant force acting on the block.

A. 2500 N

Correct B. 5000 N

C. 7500 N

D. 10000 N

Correct Answer: B

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Question 8

A radioactive sample has a half-life of 10 years. If the initial activity is 1000 Bq, calculate the activity after 20 years.

Correct A. 125 Bq

B. 250 Bq

C. 500 Bq

D. 1000 Bq

Correct Answer: A

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Question 9

A coil of wire has a resis\tance of 10 ohms and an induc\tance of 0.1 H. If a current of 2 A is flowing through the coil, calculate the induced emf.

A. 0.2 V

B. 0.4 V

Correct C. 0.6 V

D. 0.8 V

Correct Answer: C

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Question 10

A wave has a frequency of 50 Hz and a wavelength of 0.1 m. If the wave is traveling through a medium with a speed of 100 m/s, calculate the wave number.

A. 200 rad/m

B. 400 rad/m

Correct C. 600 rad/m

D. 800 rad/m

Correct Answer: C

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Question 11

A particle of mass $m$ is attached to a spring with spring cons\tant $k$. If the particle is displaced by a dis\tance $x$ from its equilibrium position and released from rest, its subsequent motion is described by the equation $x(t) = A \cos$ omega t + phi $$, where $A$ is the amplitude of the motion, $omega$ is the angular frequency, and $phi$ is the phase angle. If the particle is observed to have a maximum speed of $v_{max} = 2\sqrt{2} , \text{m/s}$, what is the value of the spring cons\tant $k$?

A. 10 N/m

B. 20 N/m

Correct C. 30 N/m

D. 40 N/m

Correct Answer: C

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Question 12

A capacitor consists of two parallel plates, each of area $A$ and separation $d$. The plates are charged to a potential difference $V$ and then connected to a battery of emf $E$. If the battery is removed and the capacitor is left to discharge, what is the time cons\tant of the discharge?

Correct A. RC

B. RC/2

C. RC/3

D. RC/4

Correct Answer: A

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Question 13

A block of mass $m$ is susp\ended from a spring with spring cons\tant $k$. If the block is displaced by a dis\tance $x$ from its equilibrium position and released from rest, its subsequent motion is described by the equation $x(t) = A \cos$ omega t + phi $$, where $A$ is the amplitude of the motion, $omega$ is the angular frequency, and $phi$ is the phase angle. If the block is observed to have a maximum speed of $v_{max} = 2\sqrt{2} , \text{m/s}$, what is the value of the spring cons\tant $k$?

A. 10 N/m

B. 20 N/m

Correct C. 30 N/m

D. 40 N/m

Correct Answer: C

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Question 14

A capacitor consists of two parallel plates, each of area $A$ and separation $d$. The plates are charged to a potential difference $V$ and then connected to a battery of emf $E$. If the battery is removed and the capacitor is left to discharge, what is the time cons\tant of the discharge?

Correct A. RC

B. RC/2

C. RC/3

D. RC/4

Correct Answer: A

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Question 15

A block of mass $m$ is susp\ended from a spring with spring cons\tant $k$. If the block is displaced by a dis\tance $x$ from its equilibrium position and released from rest, its subsequent motion is described by the equation $x(t) = A \cos$ omega t + phi $$, where $A$ is the amplitude of the motion, $omega$ is the angular frequency, and $phi$ is the phase angle. If the block is observed to have a maximum speed of $v_{max} = 2\sqrt{2} , \text{m/s}$, what is the value of the spring cons\tant $k$?

A. 10 N/m

B. 20 N/m

Correct C. 30 N/m

D. 40 N/m

Correct Answer: C

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Question 16

A particle of mass $m$ and charge $q$ is moving in a circular path of radius $r$ in a uniform magnetic field of strength $B$. If the particle's speed is $v$, what is the magnitude of the magnetic force acting on it?

Correct A. \frac{mv^2}{r}

B. \frac{mv^2}{2r}

C. \frac{mv^2}{3r}

D. \frac{mv^2}{4r}

Correct Answer: A

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Question 17

A block of mass $m$ is attached to a horizontal, massless 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 block undergoes simple harmonic motion, what is the maximum speed of the block?

Correct A. \sqrt{\frac{kx^2}{m}}

B. \sqrt{\frac{kx^2}{2m}}

C. \sqrt{\frac{kx^2}{3m}}

D. \sqrt{\frac{kx^2}{4m}}

Correct Answer: A

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Question 18

A parallel-plate capacitor has plates of area $A$ and separation $d$. The capacitor is charged to a potential difference $V$. What is the energy stored in the capacitor?

Correct A. \frac{1}{2}CV^2

B. \frac{1}{2}AV^2

C. \frac{1}{2}dV^2

D. \frac{1}{2}AVd

Correct Answer: A

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Question 19

A photon of energy $E$ is incident on a metal surface. If the work function of the metal is $\phi$, what is the maximum kinetic energy of the ejected electron?

Correct A. E - \phi

B. E + \phi

C. \phi - E

D. \phi + E

Correct Answer: A

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Question 20

A heat engine operates between two temperatures $T_1$ and $T_2$. If the engine has an efficiency of $\eta$, what is the ratio of the temperatures?

Correct A. \frac{T_1}{T_2} = \frac{1}{\eta}

B. \frac{T_1}{T_2} = \eta

C. \frac{T_1}{T_2} = \frac{\eta}{1}

D. \frac{T_1}{T_2} = \frac{1}{1 - \eta}

Correct Answer: A

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Question 21

A parallel plate capacitor has plates of area 0.04 m^2 and separation 0.02 m. If the dielectric cons\tant of the material between the plates is 3, calculate the capaci\tance.

A. 1.6 x 10^-10 F

Correct B. 3.2 x 10^-10 F

C. 4.8 x 10^-10 F

D. 6.4 x 10^-10 F

Correct Answer: B

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Question 22

A particle of mass 0.5 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 from rest, calculate the maximum speed of the particle.

A. 0.2 m/s

B. 0.4 m/s

Correct C. 0.6 m/s

D. 0.8 m/s

Correct Answer: C

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Question 23

A circuit consists of a 12 V battery, a 4 Ω resistor, and a 6 Ω resistor connected in parallel. If the current through the 4 Ω resistor is 2 A, calculate the current through the 6 Ω resistor.

A. 1 A

Correct B. 2 A

C. 3 A

D. 4 A

Correct Answer: B

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Question 24

A gas expands from an initial volume of 0.5 m^3 to a final volume of 1.5 m^3 at a cons\tant temperature of 300 K. Calculate the work done by the gas.

A. 150 J

B. 300 J

Correct C. 450 J

D. 600 J

Correct Answer: C

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Question 25

A particle of mass 0.2 kg is moving in a circular path with a radius of 0.5 m. If the particle has a speed of 2 m/s, calculate the centripetal acceleration.

A. 0.1 m/s^2

B. 0.2 m/s^2

Correct C. 0.3 m/s^2

D. 0.4 m/s^2

Correct Answer: C

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