POST UTME REDEEMERS UNIVERSITY 2019 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A radioactive sample of Δₗ emits Δₗα particles with a half-life of 5.27 years. If the initial activity of the sample is 2.5 × 10¹ Bq, what is the activity of the sample after 10 years?
A. 1.25 × 10¹ Bq
B. 2.5 × 10¹ Bq
C. 5 × 10¹ Bq
D. 7.5 × 10¹ Bq
Question 2
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 subject to a centripetal force of 15 N, what is the magnitude of the acceleration of the particle?
A. 12 m/s^2
B. 15 m/s^2
C. 18 m/s^2
D. 20 m/s^2
Question 3
A radioactive sample decays from 100 g to 50 g in 10 days. If the decay cons\tant is 0.05/day, what is the half-life of the sample?
A. 14 days
B. 16 days
C. 18 days
D. 20 days
Question 4
A magnetic field of 2 T is applied to a coil of 50 turns and a radius of 0.1 m. If the current in the coil is 5 A, what is the magnitude of the torque experienced by the coil?
A. 0.5 Nm
B. 1 Nm
C. 1.5 Nm
D. 2 Nm
Question 5
A ray of light passes from air into a glass of re\fractive index 1.5. If the angle of incidence is 30°, what is the angle of re\fraction?
A. 20°
B. 25°
C. 30°
D. 35°
Question 6
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 acceleration of 2 m/s^2, what is the magnitude of the force acting on the particle?
A. 8 N
B. 10 N
C. 12 N
D. 16 N
Question 7
A particle of mass 1 kg is moving in a straight line with an initial velocity of 5 m/s. If the particle is subjected to a force of 2 N, what is the acceleration of the particle after 2 seconds?
A. 1 m/s^2
B. 2 m/s^2
C. 3 m/s^2
D. 4 m/s^2
Question 8
A circuit consists of a 12 V battery, a 4 Ω resistor, and a 6 Ω resistor connected in series. If the current in the circuit is 2 A, what is the total resis\tance in the circuit?
A. 10 Ω
B. 12 Ω
C. 14 Ω
D. 16 Ω
Question 9
A sound wave with a frequency of 200 Hz and a wavelength of 1.5 m is traveling through a medium. If the speed of the wave is 300 m/s, what is the amplitude of the wave?
A. 0.1 m
B. 0.2 m
C. 0.3 m
D. 0.4 m
Question 10
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, calculate the force exerted by the spring.
A. 20 N
B. 40 N
C. 60 N
D. 80 N
Question 11
A beam of light is incident on a glass slab at an angle of 45°. If the re\fractive index of glass is 1.5, calculate the angle of re\fraction u\sing Snell's law.
A. 30°
B. 45°
C. 60°
D. 75°
Question 12
A radioactive sample decays at a rate of 0.5% per hour. If the initial activity is 1000 Bq, calculate the activity after 2 hours.
A. 900 Bq
B. 950 Bq
C. 1000 Bq
D. 1050 Bq
Question 13
A circuit consists of a resistor $R$, an inductor $L$, and a capacitor $C$ connected in series. If the circuit is driven by an alternating current source with a frequency of $f$, what is the impedance of the circuit?
A. \( R + jomega L + \frac{1}{jomega C} \)
B. \( R + jomega L - \frac{1}{jomega C} \)
C. \( R - jomega L + \frac{1}{jomega C} \)
D. \( R - jomega L - \frac{1}{jomega C} \)
Question 14
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. 6 m/s^2
B. 12 m/s^2
C. 18 m/s^2
D. 24 m/s^2
Question 15
A simple harmonic motion has a maximum displacement of 2.0 m and a period of 4.0 s. What is the angular frequency?
A. 0.50 rad/s
B. 1.0 rad/s
C. 2.0 rad/s
D. 4.0 rad/s

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