The sensation of fatigue in the muscles after prolonged strenuous physical work is caused by

Which one of the following cell organelles is enclosed by a single membrane?

The first line in the Lyman series has wavelength $\lambda$. The wavelength of the first line in the Balmer series is:

The sum of all the solution $(s)$ of the equation $\sin^{-1} 2x = \cos^{-1} x$ is

In a certain test there are $n$ questions. In the test,${2^{n - i}}$ students gave wrong answers to at least $i$ questions,where $i = 1, 2, \dots, n$. If the total number of wrong answers given is $2047$,then $n$ is equal to:

$A$ meter scale is supported on a wedge at its center of gravity. $A$ body of weight '$w$' is suspended from the $20 \text{ cm}$ mark and another weight of $25 \text{ g}$ is suspended from the $74 \text{ cm}$ mark. The system is balanced and the meter scale remains perfectly horizontal. Neglecting the weight of the meter scale,the weight of the body '$w$' is: (in $\text{ g}$)