What is meant by $Tin$ plague?

The differential equation of all circles which pass through the origin and whose centres lie on the $Y$-axis is

Consider the following reaction: $A \longrightarrow \text{Products}$. This reaction is completed in $100 \ min$. The rate constant of this reaction at $t_1 = 10 \ min$ is $10^{-2} \ min^{-1}$. What is the rate constant (in $min^{-1}$) at $t_2 = 20 \ min$?

The area (in square unit) of the region enclosed by the curves $y=x^2$ and $y=x^3$ is

$\int \frac{dx}{\sqrt{x-x^2}}$ is equal to

An electromagnetic wave with frequency $\omega$ and wavelength $\lambda$ travels in the $+y$ direction. Its magnetic field is along the $+x$ axis. The vector equation for the associated electric field (of amplitude $E_0$) is: