In a stationary wave,which of the following statements is correct regarding strain?

$A$ stretched string is vibrating in its $5^{th}$ harmonic as shown. Consider a particle $1$ (figure). At an instant,this particle is at its mean position and is moving towards its negative extreme. Which of the following sets of particles are in the same phase as particle $1$?

The vibrations of a string of length $60 \, cm$ fixed at both ends are represented by the equation $y = 2 \sin \left( \frac{4 \pi x}{15} \right) \cos (96 \pi t)$,where $x$ and $y$ are in $cm$. The maximum number of loops that can be formed in it is

The equation of a stationary wave is $ y = 2 \sin \left( \frac{\pi x}{15} \right) \cos (48 \pi t) $. The distance between a node and its next antinode is (in $units$)

In stationary waves,antinodes are the points where there is

$A$ string of length $0.5 \text{ m}$ and mass $10^{-3} \text{ kg}$ is tightly clamped at its ends. The tension in the string is $0.8 \text{ N}$. Identical wave pulses are produced at one end at equal intervals of time $\Delta t$. What is the minimum value of $\Delta t$ which allows constructive interference between successive pulses (in $\text{ s}$)?