C

2010015204

Level: 
C
What is the height of a computer screen if the ratio of its width and height is \( 16:9 \) and the computer has \( 23 \)-inch monitor? Round the result to two decimal places. (\( 1 \) inch=\( 2.54\,\mathrm{cm} \))
\( 28.64\,\mathrm{cm} \)
\(50.92\,\mathrm{cm} \)
\( 20.05\,\mathrm{cm} \)
\(11.28\,\mathrm{cm} \)

2010014804

Level: 
C
Find the true statement about the function \( f(x)=\left|x^4-1\right| \).
The function \( f \) has the minima at \( x=-1 \) and \( x=1 \).
The function \( f \) has no minimum.
The function \( f \) has the minimum at \( x=0 \).
The function \( f \) has the minima at \( x=-1 \), \(x=0\) and \( x=1 \).

2010014706

Level: 
C
In the experimental process, the ideal gas is expanded adiabatically from an initial volume of \(V_1=0.3\,\mathrm{m}^3\) to a final volume of \(V_2=0.8\,\mathrm{m}^3\). Find a work done by the gas in the given process. Hint: An adiabatic process with an ideal gas follows the relationship \(pV^{1.4}=c\), where \(p\) is a gas pressure, \(V\) is a gas volume, and \(c\) is a positive constant. The work \(W\) done by a gas is defined as \(W=\int_{V_1}^{V_2}p\mathrm{d}V\).
\( W\doteq 1.313c\,\mathrm{J}\)
\( W \doteq 0.375c\,\mathrm{J}\)
\( W \doteq 6.782c\,\mathrm{J}\)
\( W \doteq 0.221c\,\mathrm{J}\)

2010014705

Level: 
C
In the experimental process, the ideal gas is expanded isothermally from an initial pressure of \(0.8\,\mathrm{MPa}\) and volume of \(V_1=0.3\,\mathrm{m}^3\) to a final volume of \(V_2=1.2\,\mathrm{m}^3\). Find a work done by the gas in the given process. Hint: During isothermal expansion, both pressure \(p\) and volume \(V\) change along an isotherm with a constant \(pV\) product. The work \(W\) done by a gas is defined as \(W=\int_{V_1}^{V_2}p\mathrm{d}V\).
\( W\doteq 333\,\mathrm{kJ}\)
\( W \doteq 216\,\mathrm{kJ}\)
\( W \doteq 720\,\mathrm{kJ}\)
\( W \doteq 178\,\mathrm{kJ}\)

2010014704

Level: 
C
The time characteristic of an alternating current \(i\) is given in the figure. Find the effective value \(I\) of the alternating current \(i\) provided the following relation holds: \(I^2T=\int_0^T i^2\mathrm{d}t\).
\( I=500\,\mathrm{mA}\)
\( I=354\,\mathrm{mA}\)
\( I=0\,\mathrm{mA}\)
\( I=250\,\mathrm{mA}\)

2010014703

Level: 
C
The time characteristic of an alternating voltage \(u\) is given in the figure. Find the effective value \(U\) of the alternating voltage \(u\) provided the following relation holds: \(U^2T=\int_0^T u^2\mathrm{d}t\).
\( U=325\,\mathrm{V}\)
\( U\doteq 230\,\mathrm{V}\)
\( U=0\,\mathrm{V}\)
\( U=\frac{325}2\,\mathrm{V}\)