$A$ thin liquid film formed between a $U$-shaped wire and a light slider supports a weight of $1.5 \times 10^{-2} \ N$ (see figure). The length of the slider is $30 \ cm$ and its weight is negligible. The surface tension of the liquid film is (in $N/m$)

Diffusion current in a $p$-$n$ junction is greater than the drift current in magnitude when:

Which is the tallest tree?

Pure $Si$ at $500\, K$ has equal number of electron $(n_e)$ and hole $(n_h)$ concentrations of $1.5 \times 10^{16} \,m^{-3}$. Doping by indium increases $n_h$ to $4.5 \times 10^{22} \,m^{-3}$. The doped semiconductor is of

What product is obtained from the reaction of a Grignard reagent with a ketone?

$A$ ray of light is incident normally on a glass slab of thickness $5 ~cm$ and refractive index $1.6$. The time taken by a ray to travel from the source to the surface of the slab is the same as the time taken to travel through the glass slab. The distance of the source from the surface is (in $~cm$)