List of practice Questions

A chemical $'A?$ is used for the preparation of washing soda to recover ammonia. When $CO_2$ is bubbled through an aqueous solution of $'A?$, the solution turns milky. It is used in white washing due to disinfectant nature. What is the chemical formula of $'A'$ ?
A child is standing at one end of a long trolley moving with a speed $v$ on a smooth horizontal floor. If the child starts running towards the other end of the trolley with a speed $u$, the centre of mass of the system (trolley + child) will move with a speed
A child is standing with his two arms outstretched at the centre of a turntable that is rotating about its central axis with an angular speed $\omega_0$ . Now, the child folds his hands back so that moment of inertia becomes $3$ times the initial value. The new angular speed is
A charged particle with charge $q$ enters a region of constant, uniform and mutually orthogonal fields $\vec{E}$ and $\vec{B}$ with a velocity $\vec{V}$ perpendicular to both $\vec{E}$ and $\vec{B}$, and comes out without any change in its magnitude or direction Then
A chelating agent has two or more than two donor atoms to bind to a single metal ion. Which of the following is not a chelating agent?
A charged particle of charge Q arid mass m moves with velocity v in a circular path due to transverse magnetic field, B, then its frequency is
A charged oil drop is suspended in uniform field of $3 \times 10^4\, V/m$ so that it neither falls nor rises. The charge on the drop will be (Take the mass of the charge $= 9.9 \times 10^{-15}\, kg$ and $g = 10\, m/s^2)$
A certain radioactive substance has a half-life of 5 years. Thus for a nucleus in a sample of the element, the probability of decay in ten years is
A chain reaction in fission of Uranium is possible because
A certain compound $X$ imparts a golden yellow flame. When zinc powder is heated with concentrated solution of $X$, $H_2$ gas is evolved. $X$ combines with $CO_2$ to give a salt $Y$. $Y$ is a hydrated salt which on reaction with $HCl$ or excess of $CO_2$ gives another salt $Z$ which is an important part of baking powder. Identify $X$, $Y$ and $Z$.
A certain current liberate 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution ?
A certain compound has a formula $ {C_3H_6O}$. It combines with hydroxylamine to form two compounds which are geometrical isomers of each other. It is
Phloem sap contains
When a plant part undergoes sensence, the nurients may be
A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of 140?. The fall of temperature as registered by the Centigrade thermometer is:
In guard cells, starch gets hydrolysed under condition of
Opening of stomata requires
In contact with moisture dry cobalt chloride paper turns
Who proved that upward transport of minerals occurs through xylem
A cell's division time is $1$ minute. In $20$ minutes, a culture tube (culture medium) is $1/8^{th}$ filled with cells. When the tube will be fully filled?
Imbibition pressure develops due to
Units of water transpired by a plant for synthesis of one unit of dry matter is called
A cart is moving horizontally along a straight line with constant speed 30 m/s. A projectile is to be fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (Relative to the cart) must the projectiie be fired? (Take g = $ 10 \, ms^{ - 2} $ )
A cavity of radius $\frac{R}{2}$ is made inside a solid sphere of radius R . The center of the cavity is located at a distance $\frac{r}{2}$ from the center of sphere. The gravitational force on a particle of mass m at a distance $\frac{R}{2}$ from the center of the sphere on the line joining both the centers of sphere and cavity is ( opposite to the center of cavity ) [ here $g=\frac{GM}{R^2}$ where M the mass of the sphere ].
A card from a pack of $52$ cards is lost. From the remaining cards of the pack, two cards are drawn and are found to be both clubs. Find the probability of the lost card being a club.