Class 11th

In an experiment to verify Stokes law, a small spherical ball of radius r and density ρ falls under gravity through a distance h in air before entering a tank of water. If the terminal velocity of the ball inside water is same as its velocity just before entering the water surface, then the value of h is proportional to: (ignore viscosity of air)

The acceleration due to gravity on the earth's surface at the poles is g an and angular velocity of the earth about the axis passing through the pole is ω. An object is weight at the equator and at a height h above the poles by using a spring balance. If the weights are found to be same, then h is : (h << R, where R is the radius of the earth)

The first ionization energy (in $\mathrm{k}\mathrm{J}/\mathrm{m}\mathrm{o}\mathrm{l}$  $$ ) of $\mathrm{N}\mathrm{a},\mathrm{M}\mathrm{g},\mathrm{A}\mathrm{l}$ $$ and Si respectively, are :

A spaceship in space sweeps stationary interplanetary dust. As a result, its mass increases at a rate dm(t)/dt$$ =bv^2(t), where v(t)$$ its instantaneous velocity. The instantaneous acceleration of the satellite is:

A driver in a car, approaching a vertical wall notices that the frequency of his car horn, has changed from 400 Hz$\frac{}{{}_{}}\frac{}{{}_{}{}^{}}$ to 400 Hz$\frac{}{{}_{}{}^{}}$ , when it gets reflected from the wall. If the speed of sound in air is 345 m/s$$ , then the speed of the car is:

For the Balmer series in the spectrum of $$ $\mathrm{H}$ atom, $\bar{v}={\mathrm{R}}_{\mathrm{H}}\left\{\frac{1}{{\mathrm{n}}_1^2}-\frac{1}{{\mathrm{n}}_2^2}\right\}$ $\stackrel{}{}{}_{}\left\{\frac{}{{}_{}^{}}\frac{}{{}_{}^{}}\right\}$ the correct statements among (I) to (IV) are :

(I) As wavelength decreases, the lines in the series converge

(II) The integer $\mathrm{n}1$ $$ is equal to 2

(III) The lines of longest wavelength corresponds to $n_2=3$ ${}_{}$

(IV) The ionization energy of hydrogen can be calculated from wave number of these lines

In adiabatic process, the density of a diatomic gas becomes 32 times its initial value. The final pressure of the gas is found to be $n$ $$ times the initial pressure. The value of $n$ $$ is:

The strength of an aqueous $$ $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$ solution is most accurately determined by titrating : (Note : consider that an appropriate indicator is used)

Two different wires having lengths $L_1$ ${}_{}$ and ${}_{}$ $L_2$ , and respective temperature coefficient of linear 4expansion ${\alpha }_1$ ${}_{}$ and ${\alpha }_2$ ${}_{}$ , are joined end-to-end. Then the effective temperature coefficient of linear expansion is:

The stoichiometry and solubility product of a salt with the solubility curve given below is, respectively: