Which of the following is not an antibiotic?

Which tissue is mainly composed of fat-storing cells?

The number of disulphide linkages present in insulin are

The half-life period of a radioactive element $X$ is the same as the mean life time of another radioactive element $Y$. Initially,they have the same number of atoms. Then:

Two identical conducting spheres having unequal positive charges $q_1$ and $q_2$ are separated by a distance $r$. If they are made to touch each other and then separated again to the same distance,the electrostatic force between them in this case will be:

$A$ sound absorber attenuates the sound level by $20\, dB$. The intensity decreases by a factor of