What does the given structural formula represent?

If $^nP_4 = 30 \times ^nC_5$,then $n = \dots$

Which one of the following reactions does not form a gaseous product?

The work functions for metals $A, B$ and $C$ are respectively $1.92\, eV, 2.0\, eV$ and $5\, eV$. According to Einstein's photoelectric equation,which of these metals will emit photoelectrons for an incident radiation of wavelength $4100\, \mathring{A}$?

The equivalent capacitance between points $A$ and $B$ of the circuit shown will be

If $200 \text{ MeV}$ of energy is released in the fission of one nucleus of ${}_{92}^{236}U$,the number of nuclei that must undergo fission to release an energy of $1000 \text{ J}$ is