What is the percentage of lead in a lead pencil (in $\%$)?

We consider the radiation emitted by the human body. Which of the following statements is true?

Which part of the human brain controls the breathing movements?

If $C_p$ and $C_v$ denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively,then

Protein can be most easily removed from which of the following?

$A$ meter bridge is set up as shown,to determine an unknown resistance '$X$' using a standard $10 \, \Omega$ resistor. The galvanometer shows a null point when the tapping-key is at the $52 \, cm$ mark. The end corrections are $1 \, cm$ and $2 \, cm$ respectively for the ends $A$ and $B$. The determined value of '$X$' is $.......... \Omega$.