The ratio of surface tensions of mercury and water is given to be \(7.5\) while the ratio of their densities is \(13.6\). Their contact angles, with glass, are close to \(135^o\) and \(0^o\), respectively. It is observed that mercury gets depressed by an amount \(h\) in a capillary tube of radius \(r_1\), while water rises by the same amount \(h\) in a capillary tube of radius \(r_2\). The ratio, \((r_1/r_2)\), is then close to

In Young's double slits experiment, the position of \(5^{\text {th }}\) bright fringe from the central maximum is \(5\,cm\). The distance between slits and screen is \(1\,m\) and wavelength of used monochromatic light is \(600\,nm\). The separation between the slits is \(........\mu m\)

An upright object is placed at a distance of \(40\, cm\) in front of a convergent lens of focal length \(20\, cm\). A convergent mirror of focal length \(10\, cm\) is placed at a distance of \(60\, cm\) on the other side of the lens. The position and size of the final image will be

An object is located at \(2\, km\) beneath the surface of the water. If the fractional compression \(\frac{\Delta V }{ V }\) is \(1.36\, \%,\) the ratio of hydraulic stress to the corresponding hydraulic strain will be ......... . [Given : density of water is \(1000\, kg m ^{-3}\) and \(\left. g =9.8 \,ms ^{-2} .\right]\)

Which level of the single ionized carbon has the same energy as the ground state energy of hydrogen atom ?

A parallel plate capacitor was made with two rectangular plates, each with a length of \(l=3 \mathrm{~cm}\) and breath of \(\mathrm{b}=1 \mathrm{~cm}\). The distance between the plates is \(3 \mu \mathrm{~m}\). Out of the following, which are the ways to increase the capacitance by a factor of 10 ?
A. \(l=30 \mathrm{~cm}, \mathrm{~b}=1 \mathrm{~cm}, \mathrm{~d}=1 \mu \mathrm{~m}\)
B. \(l=3 \mathrm{~cm}, \mathrm{~b}=1 \mathrm{~cm}, \mathrm{~d}=30 \mu \mathrm{~m}\)
C. \(l=6 \mathrm{~cm}, \mathrm{~b}=5 \mathrm{~cm}, \mathrm{~d}=3 \mu \mathrm{~m}\)
D. \(l=1 \mathrm{~cm}, \mathrm{~b}=1 \mathrm{~cm}, \mathrm{~d}=10 \mu \mathrm{~m}\)
E. \(l=5 \mathrm{~cm}, \mathrm{~b}=2 \mathrm{~cm}, \mathrm{~d}=1 \mu \mathrm{~m}\)
Choose the correct answer from the options given below:

A radioactive nucleus can decay by two different processes. Half-life for the first process is \(3.0\, hours\) while it is \(4.5\, hours\) for the second process. The effective half- life of the nucleus will be \(.........\,hours.\)

An atom absorbs a photon of wavelength \(500\,nm\) and emits another photon of wavelength \(600\,nm\). The net energy absorbed by the atom in this process is \(n \times 10^{-4}\,eV\). The value of \(n\) is ............ [Assume the atom to be stationary during the absorption and emission process] \(\left(\right.\)Take \(h =6.6 \times 10^{-34}\,Js\) and \(\left.c =3 \times 10^8\,m / s \right)\)

A \(60\; HP\) electric motor lifts an elevator having a maximum total load capacity of \(2000\; \mathrm{kg}\). If the frictional force on the elevator is \(4000 \;\mathrm{N}\). the speed of the elevator at full load is close to ..............  \(\mathrm{m} / \mathrm{s}\) \(\left(1 \;\mathrm{HP}=746 \;\mathrm{W}, \mathrm{g}=10\; \mathrm{ms}^{-2}\right)\)

Let \(N\) denote the set of all natural numbers. Define two binary relations on \(N\) as \(R_1 = \{(x,y) \in  N \times  N : 2x + y= 10\}\) and \(R_2 = \{(x,y) \in  N\times  N : x+ 2y= 10\} \). Then

The number of ways in which \(21\) identical apples can be distributed among three children such that each child gets at least \(2\) apples, is

A negative test charge is moving near a long straight wire carrying a current. The force acting on the test charge is parallel to the direction of the current. The motion of the charge is

If the solution curve \(y=y(x)\) of the differential equation \(y ^{2} dx +\left( x ^{2}- xy + y ^{2}\right) dy =0\), which passes through the point \((1,1)\) and intersects the line \(y=\sqrt{3} x\) at the point \((\alpha, \sqrt{3} \alpha)\), then value of \(\log _{e}(\sqrt{3} \alpha)\) is equal to