Which phylum is characterized by the presence of a central cavity known as the spongocoel?

$A$ particle of mass $m_1$ is moving with a velocity $v_1$ and another particle of mass $m_2$ is moving with a velocity $v_2$. Both of them have the same momentum,but their kinetic energies are $E_1$ and $E_2$ respectively. If $m_1 > m_2$,then:

The product of the perpendicular distances from any point on the hyperbola $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ to its asymptotes is

The solution of $\frac{dy}{dx} = (\frac{x}{y})^{-1/3}$ is

Young's double-slit experiment is carried out by using green,red,and blue light,one color at a time. The fringe widths recorded are $\beta_G, \beta_R$,and $\beta_B$ respectively. Then:

Which of the following statements is incorrect regarding $DDT$?