Propanal on treatment with dilute sodium hydroxide forms

The extension in a string,obeying Hooke's law,is $x$. The speed of sound in the stretched string is $v$. If the extension in the string is increased to $1.5x$,the speed of sound will be (in $, v$)

$A$ telescope has an objective lens of focal length $150 \ cm$ and an eyepiece of focal length $5 \ cm$. If a $50 \ m$ tall tower at a distance of $1 \ km$ is observed through this telescope in normal setting,the angle formed by the image of the tower is $\theta$ (in degrees),then $\theta$ is close to..... (in $^{\circ}$)

$A$ spherical hollow is made in a lead sphere of radius $R$,such that its surface touches the outside surface of the lead sphere and passes through the center. What is the shift in the center of mass of the lead sphere due to the hollowing?

Two blocks of masses $1 \ kg$ and $2 \ kg$ are connected by a metal wire going over a smooth pulley. The breaking stress of the metal is $\frac{40}{3 \pi} \times 10^6 \ N m^{-2}$. What should be the minimum radius of the wire used if it should not break (in $mm$)? $\left(g = 10 \ m s^{-2}\right)$

$A$ projectile is fired at an angle of $45^\circ$ with the horizontal. The elevation angle of the projectile at its highest point as seen from the point of projection is: