The curve between charge density and distance near a $P-N$ junction will be:

The natural frequency of an $L-C$ circuit is $1,25,000 \text{ cycles/s}$. Then the capacitor $C$ is replaced by another capacitor with a dielectric medium of dielectric constant $K$. In this case,the frequency decreases by $25 \text{ kHz}$. The value of $K$ is

$A$ person speaking normally produces a sound intensity level of $40\, dB$ at a distance of $1\, m$. If the threshold intensity level for reasonable audibility is $20\, dB$,the maximum distance at which he can be heard clearly is ..... $m$.

The heat evolved in the combustion of methane is given by the following equation:
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)};$
$\Delta H = -890.3 \, kJ$
How many grams of methane would be required to produce $445.15 \, kJ$ of heat of combustion?

The $\Delta H_f^o$ for $CO_{2(g)}$,$CO_{(g)}$ and $H_2O_{(g)}$ are $-393.5$,$-110.5$ and $-241.8 \ kJ \ mol^{-1}$ respectively. The standard enthalpy change (in $kJ$) for the reaction $CO_{2(g)} + H_{2(g)} \to CO_{(g)} + H_2O_{(g)}$ is

What is the figure given below showing in particular?