Class 11th

Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to achieve $$ $10\mathrm{p}\mathrm{p}\mathrm{m}$ of iron in $$ $100\mathrm{k}\mathrm{g}$ of wheat is Atomic weight : $$ $\mathrm{F}\mathrm{e}=55.85;\mathrm{S}=32.00;\mathrm{O}=16.00$

The velocity (v) and time (t) graph of a body in a straight line motion is shown in the figure. The point S is at 4.333 seconds. The total distance covered by the body in 6 s is:

A ring is hung on a nail. It can oscillate, without slipping or sliding (i) in its plane with a time period T?, and, T (ii) back and forth in a direction perpendicular to its plane, with a period T?. The ratio T?/T? will be:

The magnitude of work done by a gas that undergoes a reversible expansion along the path $ABC$ $$ shown in the figure is Pressure

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