Percentage of gold in $14$ carat gold is (in $\%$)

Find the oxidation state of sodium in $Na_{2}O_{2}$.

$\cos ^2\left(\frac{\pi}{6}+\theta\right)-\sin ^2\left(\frac{\pi}{6}-\theta\right)$ is equal to

$A$ series $LCR$ circuit is connected across a source of alternating $emf$ of changing frequency and resonates at frequency $f_0$. Keeping capacitance constant,if the inductance $(L)$ is increased by $\sqrt{3}$ times and resistance $(R)$ is increased by $1.4$ times,the resonant frequency now is

Which of the following is a low spin complex?

Passive absorption of minerals depends on which of the following?