The displacement \(x\) of a particle varies with time \(t\) as \(x=ae^{-\alpha t}+be^{\beta t}\) where \(a,b,\alpha\) and \(\beta\) are positive constants. The velocity of the particle will:
1. decrease with time
2. be independent of \(\alpha\) and \(\beta\)
3. drop to zero when \(\alpha=\beta\)
4. increase with time
A transformer having an efficiency of \(75\%\) is working on \(220~\mathrm{V}\) and \(4.4~\mathrm{kW}\) power supply. If the current in the secondary coil is \(5~\mathrm{A}\). What will be the voltage across the secondary coil and the current in the primary coil?
1. \(
V_s=220 \mathrm{~V}, I_p=20 \mathrm{~A}
\)
2. \( V_s=660 \mathrm{~V}, I_p=15 \mathrm{~A}
\)
3. \( V_s=660 \mathrm{~V}, I_p=20 \mathrm{~A}
\)
4. \( V_s=220 \mathrm{~V}, I_p=15 \mathrm{~A}\)