Two wires of same length and thickness having specific resistances \(6\, \Omega \,cm\) and \(3 \,\Omega\, cm\) respectively are connected in parallel. The effective resistivity is \(\rho\, \Omega \,cm\). The value of \(\rho\) to the nearest integer, is ..... .

A rod of length \(L\) at room temperature and uniform area of cross section \(A\), is made of a metal having coefficient of linear expansion \(\alpha {/^o}C\). It is observed that an external compressive force \(F\), is applied on each of its ends, prevents any change in the length of the rod, when it temperature rises by \(\Delta \,TK\). Young’s modulus, \(Y\), for this metal is

The position vector of a particle related to time \(t\) is given by \(\overrightarrow{ r }=\left(10 t \hat{ i }+15 t ^2 \hat{ j }+7 \hat{ k }\right) m\) The direction of net force experienced by the particle is

When radiation of wavelength \(\lambda\) is used to illuminate a metallic surface, the stopping potential is \(V.\) When the same surface is illuminated with radiation of wavelength \(3 \lambda,\) the stopping potential is \(\frac{ V }{4} .\) If the threshold wavelength for the metallic surface is \(n \lambda\) then value of \(n\) will be......

Two wavelengths \(\lambda_1\) and \(\lambda_2\) are used in Young's double slit experiment \(\lambda_1=450 \mathrm{~nm}\) and \(\lambda_2=650 \mathrm{~nm}\). The minimum order of fringe produced by \(\lambda_2\) which overlaps with the fringe produced by \(\lambda_1\) is \(n\). The value of \(n\) is _________.

Two gases-argon (atomic radius \(0.07 \;\mathrm{nm}\),atomic weight \(40\) ) and xenon (atomic radius \(0.1\; \mathrm{nm},\) atomic weight \(140\) ) have the same number density and are at the same temperature. The raito of their respective mean free times is closest to

Refer the figure given below. \(\mu_1\) and \(\mu_2\) are refractive indices of air and lens material. The height of image will be _______ cm.

Your friend is having eye sight problem. She is not able lo see clearly a distant uniform window mesh and it appears to her as non-uniform and distorted. The doctor diagnosed the problem as

A galvanometer with its coil resistance \(25\,\Omega \) requires a current of  \(1\,mA\)  for its full deflection. In order to construct an ammeter to read up to a current of \(2\,A,\)  the approximate value of the shunt resistance should be

Two ions having same mass have charges in the ratio \(1: 2\). They are projected normally in a uniform magnetic field with their speeds in the ratio \(2: 3\). The ratio of the radii of their circular trajectories is -

In a carnot engine, the temperature of reservoir is \(527^{\circ} C\) and that of \(\operatorname{sink}\) is \(200 \; K\). If the workdone by the engine when it transfers heat from reservoir to sink is \(12000 \; kJ\), the quantity of heat absorbed by the engine from reservoir is \(\times 10^{6} \; J\)