At poles, a stretched wire of a given length vibrates in unison with a tuning fork. At the equator, for same setting, to produce resonance with same fork, the vibrating length of wire

Two tuning forks of frequencies 256 Hz and 258 Hz are sounded together. The time interval between two consecutive maxima is

If a source emitting waves of frequency ' $F$ ' moves towards an observer with a velocity $\frac{\mathrm{V}}{3}$ and the observer moves away from the source with a velocity $\frac{\mathrm{V}}{4}$, the apparent frequency as heard by the observer will be ( $\mathrm{V}=$ velocity of sound)

Two sound waves travelling in the same direction have displacement $\mathrm{y}_1=\mathrm{a} \sin (0.2 \pi \mathrm{x}-50 \pi \mathrm{t})$ and $\mathrm{y}_2=\mathrm{a} \sin (0.15 \pi \mathrm{x}-46 \pi \mathrm{t})$.

How many times, a listener can hear sound of maximum intensity in one second?