Typhoid fever is caused by which of the following?

The energy emitted per second by a black body at $27^{\circ}C$ is $10 \ J$. If the temperature of the black body is increased to $327^{\circ}C$,the energy emitted per second will be ......... $J$.

Identify the incorrect statement among the following.

Which of the following salts does not produce nitrogen dioxide $(NO_2)$ upon heating?

Among the following,which is water insoluble?

The impedance of a circuit,when a resistance $R$ and an inductor of inductance $L$ are connected in series in an $AC$ circuit of frequency $f$ is