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[$A$] The time $\mathrm{T}_{A 0}=\mathrm{T}_{\mathrm{OA}}$
[$B$] The velocities of the two pulses (Pulse $1$ and Pulse $2$) are the same at the midpoint of rope.
[$C$] The wavelength of Pulse $1$ becomes longer when it reaches point $A$.
[$D$] The velocity of any pulse along the rope is independent of its frequency and wavelength.
| $(A)$ Temperature of gas is made $4$ times and pressure $2$ times | $(P)$ speed becomes $2\sqrt 2$ times |
| $(B)$ Only pressure is made $4$ times without change in temperature | $(Q)$ speed become $2$ times |
| $(C)$ Only temperature is changed to $4$ times | $(R)$ speed remains unchanged |
| $(D)$ Molecular mass of the gas is made $4$ times | $(S)$ speed remains half |
