A source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4 ms^-1 at an angle of ${60}^0$ with the source-observer line as shown in the figure. The observer is at rest. The apparent frequency observed by the observer (velocity of sound in air 330 ms^-1), is: 
              

1. 100 Hz

2. 103 Hz

3. 106 Hz

4. 97 Hz

If dimensions of critical velocity \({v_c}\) of a liquid flowing through a tube are expressed as \(\eta^{x}\rho^yr^{z}\), where \(\eta, \rho~\text{and}~r\) are the coefficient of viscosity of the liquid, the density of the liquid, and the radius of the tube respectively, then the values of \({x},\) \({y},\) and \({z},\) respectively, will be:

\(4.0~\text{gm}\) of gas occupies \(22.4~\text{litres}\) at NTP. The specific heat capacity of the gas at a constant volume is  \(5.0~\text{JK}^{-1}\text{mol}^{-1}.\) If the speed of sound in the gas at NTP is \(952~\text{ms}^{-1},\) then the molar heat capacity at constant pressure will be:
(\(R=8.31~\text{JK}^{-1}\text{mol}^{-1}\)) 

If vectors \(\overrightarrow{{A}}=\cos \omega t \hat{{i}}+\sin \omega t \hat{j}\) and \(\overrightarrow{{B}}=\cos \left(\frac{\omega t}{2}\right)\hat{{i}}+\sin \left(\frac{\omega t}{2}\right) \hat{j}\) are functions of time. Then, at what value of \(t\) are they orthogonal to one another?

In the given figure, a diode \(D\) is connected to an external resistance \(R = 100~\Omega\)$$ and an EMF of \(3.5~\text{V}\). If the barrier potential developed across the diode is \(0.5~\text{V}\), the current in the circuit will be:
  
1. \(30~\text{mA}\)
2. \(40~\text{mA}\)
3. \(20~\text{mA}\)
4. \(35~\text{mA}\)

If potential \([\text{in volts}]\) in a region is expressed as \(V[x,y,z] = 6xy-y+2yz,\) the electric field \([\text{in N/C}]\) at point \((1, 1, 0)\) is:

A remote sensing satellite of the earth revolves in a circular orbit at a height of \(0.25 \times10^6~\text{m}\) above the surface of the earth. If Earth’s radius is \(6.38\times10^6~\text{m}\) and \(g=9.8~\text{ms}^{-2},\) then the orbital speed of the satellite is:
1. \(7.76~\text{kms}^{-1}\)
2. \(8.56~\text{kms}^{-1}\)
3. \(9.13~\text{kms}^{-1}\)
4. \(6.67~\text{kms}^{-1}\)

Two metal wires of identical dimensions are connected in series. If \(\sigma_1~\text{and}~\sigma_2\) are the conductivities of the metal wires respectively, the effective conductivity of the combination is:
1. \(\dfrac{2\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)
2. \(\dfrac{\sigma_1 +\sigma_2}{2\sigma_1\sigma_2}\)
3. \(\dfrac{\sigma_1 +\sigma_2}{\sigma_1\sigma_2}\)
4. \(\dfrac{\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)

A satellite \(S\) is moving in an elliptical orbit around the Earth. If the mass of the satellite is very small as compared to the mass of the earth, then:

Two particles \({A}\) and \({B}\), move with constant velocities \(\vec{v}_1\) and \(\vec{v}_2\) respectively. At the initial moment, their position vectors are \(\vec{r}_1\) and \(\vec r_2\) respectively. The conditions for particles \({A}\) and \({B}\) for their collision will be: