Which of the following has provided the main food source for humans?

$A$ balloon is filled with $500 \ m^3$ of helium gas at $27^{\circ}C$ and $1 \ atm$ pressure. What will be the volume of helium at $3^{\circ}C$ and $0.5 \ atm$ pressure in $m^3$?

Suppose,the acceleration due to gravity at the Earth's surface is $10\, m\, s^{-2}$ and at the surface of Mars it is $4.0\, m\, s^{-2}$. $A$ $60\, kg$ passenger goes from the Earth to the Mars in a spaceship moving with a constant velocity. Neglect all other objects in the sky. Which part of the figure best represents the weight (net gravitational force) of the passenger as a function of time?

The proposition $(\sim p) \vee (p \wedge \sim q)$ is equivalent to:

$A$ rectangular loop has a sliding connector $PQ$ of length $l$ and resistance $R \, \Omega$. It is moving with a speed $v$ as shown. The setup is placed in a uniform magnetic field directed into the plane of the paper. The three currents $I_1$, $I_2$, and $I$ are:

$A$ primary coil and a secondary coil are placed close to each other. $A$ current, which changes at the rate of $25 \, A$ in a millisecond, is present in the primary coil. If the mutual inductance is $92 \times 10^{-6} \, H$, then the value of the induced emf in the secondary coil is: