POST UTME BABCOCK UNIVERSITY 2018 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A radioactive sample has a half-life of $T_{1/2}$. If the initial activity of the sample is $A_0$ and the activity at time $t$ is $A(t)$, what is the ratio of the activity at time $t$ to the initial activity?
A. \left\( \frac{1}{2}\right \)^{t/T_{1/2}}
B. \left\( \frac{1}{2}\right \)^{T_{1/2}/t}
C. \left\( \frac{1}{2}\right \)^{t/T_{1/2}} + \left\( \frac{1}{2}\right \)^{T_{1/2}/t}
D. \left\( \frac{1}{2}\right \)^{t/T_{1/2}} - \left\( \frac{1}{2}\right \)^{T_{1/2}/t}
Question 2
A light ray passes from air into a glass slab 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 3
A wave has a frequency of 100 Hz and a wavelength of 0.5 m. What is the speed of the wave?
A. 50 m/s
B. 60 m/s
C. 70 m/s
D. 80 m/s
Question 4
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 maximum velocity of the particle?
A. 0.2 m/s
B. 1.0 m/s
C. 2.0 m/s
D. 4.0 m/s
Question 5
A gas is heated from 300 K to 400 K at cons\tant volume. If the initial pressure is 1 atm, calculate the final pressure.
A. 1.33 atm
B. 1.5 atm
C. 1.67 atm
D. 2 atm
Question 6
A 2.5 kg block of ice at 0°C is placed in a 10°C water bath. Assuming the specific heat capacity of ice is 2090 J/(kg·K) and the specific heat capacity of water is 4186 J/(kg·K), calculate the time it takes for the ice to melt completely.
A. 10 minutes
B. 20 minutes
C. 30 minutes
D. 40 minutes
Question 7
A 5 kg block is projected up a 30° inclined plane with an initial velocity of 10 m/s. Assuming the coefficient of kinetic friction is 0.2, calculate the dis\tance traveled by the block before it comes to rest.
A. 5 m
B. 10 m
C. 15 m
D. 20 m
Question 8
A 2 kg block is attached to a horizontal, massless string. The block is pulled to the right with a force of 10 N and then released from rest. What is the speed of the block when it passes through the point where it was released?
A. 2 m/s
B. 4 m/s
C. 6 m/s
D. 8 m/s
Question 9
A capacitor of capaci\tance 10 μF is connected to a battery of emf 12 V. What is the charge stored in the capacitor?
A. 120 μC
B. 240 μC
C. 360 μC
D. 480 μC
Question 10
A 5 μF capacitor is connected in series with a 10 kΩ resistor and a 20 V battery. If the initial current is 0 A, calculate the time cons\tant of the circuit.
A. 0.1 s
B. 0.5 s
C. 1.0 s
D. 2.0 s
Question 11
A wave has a frequency of 50 Hz and a wavelength of 0.2 m. Calculate the speed of the wave.
A. 10 m/s
B. 20 m/s
C. 30 m/s
D. 40 m/s
Question 12
A convex lens of focal length $f$ is placed in a beam of light. If the object dis\tance is $u$ and the image dis\tance is $v$, what is the magnification of the lens?
A. \frac{v}{u}
B. \frac{u}{v}
C. \frac{f}{u}
D. \frac{f}{v}
Question 13
A 5 kg block is projected up a 30° inclined plane with an initial velocity of 10 m/s. Assuming the coefficient of kinetic friction is 0.2, calculate the time it takes for the block to come to rest.
A. 2.5 s
B. 3.5 s
C. 4.5 s
D. 5.5 s
Question 14
A wave has a frequency of 50 Hz and a wavelength of 1 m. What is the speed of the wave?
A. 25 m/s
B. 30 m/s
C. 35 m/s
D. 40 m/s
Question 15
A gas expands from 1.5 L to 3.5 L against a cons\tant external pressure of 2.5 atm. If the initial temperature is 300 K, calculate the work done by the gas in Joules.
A. -1200 J
B. -1500 J
C. -1800 J
D. -2000 J

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