Which artificial sweetener contains chlorine?

Which of the following pairs contains structurally similar substances?

Charge $q$ is uniformly distributed over a thin half ring of radius $R$. The electric field at the centre of the ring is

The electrostatic potential inside a charged spherical ball is given by $\phi = ar^2 + b$,where $r$ is the distance from the centre and $a, b$ are constants. Then the charge density inside the ball is

Two steel wires of same length $L$ but radii $r$ and $2r$ are connected together end to end and tied to a wall as shown. $A$ force $F$ stretches the combination by $10 \ mm$. How far does the midpoint $A$ move in $mm$?

$A$ body of weight $64 ~N$ is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are $0.6$ and $0.4$ respectively,the acceleration of the body is (Acceleration due to gravity $= g$)