POST UTME COVENANT UNIVERSITY 2021 Physics | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A radioactive sample has a half-life of $T$. If the initial activity of the sample is $A$, what is the activity of the sample after a time $t$?
A. $Ae^{-\frac{t}{T}}$
B. $Ae^{-\frac{T}{t}}$
C. $Ae^{-\frac{t}{2T}}$
D. $Ae^{-\frac{2T}{t}}$
Question 2
A particle of mass $m$ is moving in a circular orbit of radius $r$ under the influence of a central force given by $F(r) = \frac{k}{r^2}$. If the particle's speed is $v$, what is the angular momentum of the particle?
A. $\frac{mv^2}{r}$
B. $\frac{mv}{r}$
C. $\frac{mv^2}{2r}$
D. $\frac{mv}{2r}$
Question 3
A circuit consists of a $10\Omega$ resistor, a $20\mu F$ capacitor, and a $5mH$ inductor in series. If the circuit is driven by a $10V$ AC source with a frequency of $50Hz$, what is the impedance of the circuit?
A. $15.9\Omega$
B. $16.2\Omega$
C. $16.5\Omega$
D. $16.8\Omega$
Question 4
A particle of mass $m$ is moving in a circular orbit of radius $r$ under the influence of a central force given by $F(r) = \frac{k}{r^2}$. If the particle's speed is $v$, what is the total energy of the particle?
A. $\frac{1}{2}mv^2 + \frac{k}{r}$
B. $\frac{1}{2}mv^2 - \frac{k}{r}$
C. $\frac{1}{2}mv^2 + \frac{k}{r^2}$
D. $\frac{1}{2}mv^2 - \frac{k}{r^2}$
Question 5
A gas is contained in a cylinder of volume $V$ at a temperature of $T$. If the gas is heated to a temperature of $2T$, what is the new volume of the gas?
A. $\frac{3}{2}V$
B. $\frac{4}{3}V$
C. $\frac{5}{4}V$
D. $\frac{6}{5}V$

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