$A$ light wave enters from medium $1$ to medium $2$. Its velocity in the $2^{nd}$ medium is double that of the $1^{st}$ medium. For total internal reflection to occur,the angle of incidence must be greater than which of the following values?

Smoke is an example of

The $pK_a$ values of four carboxylic acids are $4.76, 4.19, 0.23$,and $3.41$ respectively. The $pK_a$ value of the strongest carboxylic acid among them is

$A$ uniform cylinder of length $L$ and mass $M$ having cross-sectional area $A$ is suspended,with its length vertical,from a fixed point by a massless spring such that it is half-submerged in a liquid of density $\sigma$ at equilibrium position. The extension $x_0$ of the spring when it is in equilibrium is:

The current-voltage relation of a diode is given by $I = (e^{1000V/T} - 1) \text{ mA}$,where the applied voltage $V$ is in volts and the temperature $T$ is in Kelvin. If a student makes an error of $\mp 0.01 \text{ V}$ while measuring a current of $5 \text{ mA}$ at a temperature of $300 \text{ K}$,what will be the error in the measurement of the current in $\text{ mA}$?