The magnifying power of a refracting type of astronomical telescope is $m$. If the focal length of the eyepiece is doubled,the magnifying power will become:

In a single slit diffraction experiment, the first minimum for red light $(\lambda = 660 \, nm)$ coincides with the first secondary maximum of some other wavelength $\lambda'$. The value of $\lambda'$ is ...... $\mathring{A}$.

If the pair of straight lines given by $A x^2+2 H x y+B y^2=0$ $(H^2>A B)$ forms an equilateral triangle with the line $a x+b y+c=0$,then $(A+3 B)(3 A+B)$ is equal to :

Consider the depicted hydrogen $( H )$ in the hydrocarbons given below. The most acidic hydrogen $( H )$ is

Approximately $70\%$ of carbon dioxide absorbed by the blood is transported to the lungs:

Plants adapted to low light intensity have