Choose the correct order for the energy barrier to rotation around the B-N bond :- Options 1. H2B–NR2 < BH(NR2)2 < B(NR2)3 2. B(NR2)3 < BH(NR2)2 < BH2–NR2 3. BH(NR2)2 > B(NR2)3 > BH2–NR2 4. BH2–NR2 > B(NR2)3 > BH(NR2)2

Q. For a cone of radius 'r', height 'h' and slant height 'l', $l^2=r^2+h^2$.

Q. The height and radius of the cone of which the frustum is a part are h₁ and r₁ respectively. If h₂ and r₂ are the heights and radius of the smaller base of the frustum respectively and h₂ : h₁ = 1 : 2, then r₂ : r₁ is equal to

(a) 1 : 3

(b) 1 : 2

(c) 2 : 1

(d) 3 : 1

Q.

Parametric equation of $(x-h{)}^2+(y-k{)}^2=r^{2}arex+h=rcos\theta andy+k=rsin\theta$

Q. The resistance $R_1$ and $R_2$ are joined in parallel and a current is passed so that the amount of heat liberated is $H_1$ and $H_2$ respectively. The ratio $\frac{H_1}{H_2}$ has the value