There is a horizontal film of soap solution. On it,a thread is placed in the form of a loop. The film is pierced inside the loop,and the thread becomes a circular loop of radius $R$. If the surface tension of the soap solution is $T$,then what will be the tension in the thread?

The image of the point $(4, -13)$ with respect to the line $5x + y + 6 = 0$ is

Which of the following is the most effective in causing the coagulation of a ferric hydroxide sol?

Solar radiation emitted by the sun resembles that emitted by a black body at a temperature of $6000\, K$. Maximum intensity is emitted at a wavelength of about $4800\, \mathring{A}$. If the sun was cooled down from $6000\, K$ to $3000\, K$,then the peak intensity would occur at a wavelength of ......... $\mathring{A}$.

Water is pumped from a depth of $10\, m$ and delivered through a pipe of cross section $10^{-2}\, m^2$. If it is needed to deliver a volume of $10^{-1}\, m^3$ per second,the power required will be: ............ $kW$

One ampere of current is passed for $9650 \ s$ through molten $AlCl_3$. What is the weight in grams of $Al$ deposited at cathode? (atomic weight of $Al = 27$)