Archaeopteryx,a transitional fossil between birds and reptiles,was discovered from rocks of which of the following periods?

When light of wavelength $\lambda$ is incident on a photosensitive surface,photons of power $P$ are emitted. The number of photons $n$ emitted in $t$ seconds is (where $h$ = Planck's constant,$c$ = velocity of light in vacuum).

If $\int \frac{7x^8+8x^7}{(1+x+x^8)^2} dx = f(x) + c$,then $f(x)$ is equal to

Which of the following complex ions is not expected to absorb visible light?

$A$ musical instrument $P$ produces sound waves of frequency $n$ and amplitude $A_P$. Another musical instrument $Q$ produces sound waves of frequency $\frac{n}{4}$. The waves produced by $P$ and $Q$ have equal energies. If the amplitude of waves produced by $P$ is $A_P$,the amplitude of waves produced by $Q$ will be: (in $A_P$)

Two dice are rolled simultaneously. The probability that the sum of the two numbers on the dice is a prime number is: